Tuesday, May 03, 2016

[ilapbunp] Education as a publicly funded investment

Time point X: education institution keeps records of who it has enrolled, including demographic records of each student.  Country keeps demographic records of which demographic groups are currently earning what income (census and income tax records).

Time point Y, 45 years later:  Lifetime income of each individual can be calculated, and demographic income distribution can be compared with the income distribution at time point X.  For demographic groups which have increased in relative income earning rate compared to time X, the educational institution that had enrolled them at time point X is awarded a prize proportional to the growth, imaginable as a portion of the GDP growth that would not have occurred had they not been the educators.

Educational institutions are thus incentivized to think capitalistically: seek out underserved demographics which will offer the most bang for the buck, for which education will cause the most growth in income earning.

It may also provide incentive to define new demographic categories: the growth of a narrowly defined especially underserved demographic is not diluted by less growth of a more broadly defined demographic.

Weird unintended consequences might occur, especially since battling over proportion of income distribution is a zero-sum game.

45 years is a very long investment term, but the financial markets will figure it out.

Originally conceived just for primary education, because children don't have control over their education decisions.  Adults in secondary education seem to have incentives to maximize the benefit of their education.  Nevertheless, should the proposed scheme also be deployed for secondary education?

[iriveymg] Error correcting email addresses

Create an email domain whose addresses contain error correcting code information.  It is not defeated by bad handwriting or other transcription errors.  Easiest is probably addresses that contain only digits, including check digits.

Need to publicize a method with which a sender can detect and correct errors in a corrupted address.

Ambitiously, deploy the idea to much more than just the username part of an email address.  An entire URL.  Federated system with many possibly error correcting codes, perhaps some able to correct more errors.  Would need to redo DNS.

[qqqyxqta] Balkanize

If left to their own devices, humans naturally balkanize, perhaps breaking down into tribes of less than 100.

Is this true?

It takes something special to prevent it.  What, if anything, works?  Inspired by Christianity.

Identify the ways you have balkanized.

[xmeejiwi] Altering scanned text

Create software that makes it easy to take an digital image with text and modify the text in it.  Detect and match font, synthesize and fill in small amounts of background as necessary.

Inspired by Facebook requiring someone to submit proof of their pseudonym.

Continuing the arms race: devise methods to print text onto objects so that the text is difficult to alter.  Difficult to synthesize backgrounds.  Difficult to match fonts.

Cryptographic signatures encoded as a bar code might work, though possibly tricky if multiple people conspire to help someone, including someone who actually has the fake name.

[tafhuact] Average speed of public transportation door to door

What is the average speed, say, as the crow flies from door to door, for someone taking public transportation?

Things like automated Segway might beat it.

[ghdvbeuq] 4 chord Prelude

Adapt Bach's Prelude in C Major (Well-Tempered Clavier) to arbitrary chord patterns, including the famous patterns that appear in popular music, e.g., 12-bar blues and I-V-vi-IV.

[illbfbqv] Bad review rate

How many bad reviews a product or service has is made more interesting, and useful, by knowing the total number of sales or customers, so the rate of bad reviews.  These numbers are available, though often concealed.

Also interesting is the total number of reviews as a proportion of total sales.  This can signal that reviews are being manipulated, perhaps good reviews (or bad reviews) being purchased.

[iojfevfn] Gradients in psychedelic art

Characteristics of psychedelic art: bright colors, curves, gradients between very different colors, e.g., blue to yellow.

Made famous in images of fractals like the Mandelbrot set.

[caqemrro] Game animation as rules

Move-by-move animations of a collection of go 囲碁 would explain the rules fairly well, in case communication is difficult.  The game should be played out until all the dame are filled.  The final frame could have all the captured territories filled in, making it clear that the objective of the game is to maximize area.  With difficulty, an observer of the animation can discover the ko rule, that certain moves are forbidden even though they seem otherwise advantageous.  Komi could be depicted as extra white stones off to the side at the beginning of the game, or added at the end, or could be omitted: with great difficulty an observer could discover that black seeks to win by a margin that is not 0.

Chess could be illustrated similarly, though it seems an inherently more complicated game.  13 different pixel colors, including blank.  It is also a little bit difficult to illustrate who won (even if the game is played out to checkmate), or that the game was a draw.

[pvnveski] Assault weapon

We explore the concept of "assault" in the phrase "assault weapon" in the context of how "assault" (the threat of force) is legally distinguished from "battery" (the use of force).

On one hand, almost any gun, say, semi-automatic gun, communicates a threat of force, as perceived in the fear of those seeing it.  Does an assault weapon induce significantly more fear than any other such gun, analogous to some actions and some speech are deemed to cause a criminally high amount of fear, so become assault?

On the other hand, there are likely contexts in which assault weapons do no cause fear at all; perhaps the local population considers the weapon normal.  In such a case, the weapon ought not be classified "assault".  Following such a line of reasoning, criminal liability for such weapons would depend on their context.  But this would make it difficult or impossible to regulate them at their point of sale.

[shkrbydm] Distinctive bass line

Transcribe the bass line of Lake Street Dive's cover of "I Want You Back".  What other songs have such distinctive bass lines?

[ekhqcnmh] Kirk wakes up

Kirk hits his head when boarding the new recruit shuttle, in the J.J. Abrams Star Trek reboot.  Everything that happens afterwards is just a dream.

[vddqvvpj] Profanity and children

The way a person uses profanity is difficult to change, how they use language when not thinking about it, so therefore becomes a social class marker.  Social class markers have lifelong effects, so, assuming this model is correct, parents are justifiably concerned about what profanity their kid learns.  But there is a feeling of wasted effort in training the child merely to appear a certain way for their best chances in society, rather than the expending that effort toward more substantive education.

Vaguely related, a person's awkwardness about sex (which is the subject of much profanity) is a social class marker.

[kvjowhee] Automated music analysis for education

Given a musical song, automatically analyze it to determine all its musical characteristics, e.g., styles.  Deconstruction.  Inspired by various rhythmic musical styles.  This seems relatively straightforward with machine learning, though analogous to the difficult object recognition problem (in a complicated scene) in machine vision.

Various companies, Pandora, Google, have tried this in hopes of suggesting more music that a person will like, but have found it is not too effective.  Collaborative filtering works better.

The new tack is instead to provide it intended as a teaching tool: find me more examples of this musical "thing", an educational tool to help people compose more music.

Generalize the idea to automatically analyzing other genres of art.  Text, i.e., literary fiction.  2D paintings and photographs.  Movies (training examples could be tropes enumerated in TvTropes), though we also want things like cinematic techniques like camera work if the tool is to educate filmmakers.

[iswzbowh] Pi controversies

The Greek letter pi is involved in two mathematical controversies.

Lowercase pi is pitted against the one legged lowercase tau as the constant describing the circle.

Uppercase pi is pitted against one legged uppercase gamma as the continuous extension of the factorial function.

Vaguely relatedly, uppercase pi signifying product lives in harmony with uppercase sigma signifying sum.  Similarly lowercase pi and sigma for molecular electron orbitals.

[nbzmviyz] Forcing monoculture

The Soviets tried very hard to eliminate multiculturalism, on the assumption that monoculture creates a better, more governable state, seemingly so observed in other countries.

Income redistribution, banning of religion, single language, standardized and universal education, forced migration, mass imprisonment (gulag), pogroms, and mass executions.

On the face of it, it did not work, as seen in the breakup of the Soviet Union, as well as the many subsequent conflicts.  This is surprising, as the state was virtually unlimited in what it could do to induce monoculture.

Did they do it wrong?  Was there a better way?  Was it simply that they were not in power long enough?

If the measures done there were not effective, it calls into question similar policies being currently pursued for similar reasons in other countries: e.g., income redistribution to decrease social conflict, increased access to education to decrease social conflict.

[dzubaucb] Taking one for the team

One curious human behavior is going out of your way to hurt someone, even taking actions which may hurt yourself when being lazy is an alternative.  For example, bullying, even in the face of prohibitions and punishment for bullying.  It seems irrational.

Hypothesize the behavior is social, in particular, a way of furthering the group to which one feels a membership even if it is at a cost to oneself: taking one for the team.  Often, the group in question is rather vague, perhaps a social class.

How does the feeling of group membership develop?

We can measure the strength of group membership by measuring the willingness to take one for the team.

[iuivsafx] Sexual awkwardness as a social class marker

A person's awkwardness around sex, both in the activity itself and the various communication and courtship rituals surrounding it, do not easily change.  Both awkwardness and lack of awkwardness are difficult to fake.  Therefore, these are likely to be things people discriminate by, social class markers.  How does it play out?  Which social classes behave which way?  How is awkwardness or lack of awkwardness developed or taught?

This explains things like resistance to sex ed (also this) and shame in promiscuity.

Saturday, April 30, 2016

[ffpenile] Enacting policy with context

When enacting policy, e.g., law, let the policy also state assumptions for how the world works, a model for the world, and how the policy is expected to work within the model.

Legislators might disagree on how the world works, but might agree that the policy is a good idea.  In which case, the policy can have multiple models attached to it.

If it later becomes clear that the model described in the policy is not how the world actually works, then the law can be revisited and perhaps struck down.

[yndybayx] Game as a bomb countdown

The Atomic Bomb go 囲碁 game would be neat alternative to the bomb timer trope seen in movies.  Only those who know go 囲碁 history would recognize the game and know on which move the bomb will go off.

The following SGF game record was taken from http://www.lifein19x19.com/forum/viewtopic.php?f=10&t=1303

(;GM[1] FF[4] CA[UTF-8] AP[CGoban:3] ST[2] RU[Japanese] SZ[19] KM[0.00] GN[The Atomic Bomb Game] PW[Hashimoto Utaro] PB[Iwamoto Kaoru] WR[9p] BR[9p] DT[1945-08-06] EV[3rd Honinbo Tournement] RO[2] PC[Hiroshima] RE[W+5.00] ;B[qd] ;W[oq] ;B[od] ;W[de] ;B[dp] ;W[cn] ;B[fp] ;W[qp] ;B[dc] ;W[mc] ;B[ee] ;W[ef] ;B[ed] ;W[dg] ;B[ce] ;W[cf] ;B[be] ;W[qj] ;B[qh] ;W[gf] ;B[bf] ;W[ch] ;B[jq] ;W[oj] ;B[em] ;W[lq] ;B[rp] ;W[pp] ;B[ol] ;W[ql] ;B[ml] ;W[ko] ;B[mn] ;W[pn] ;B[co] ;W[gp] ;B[go] ;W[hp] ;B[fq] ;W[ho] ;B[hr] ;W[km] ;B[nj] ;W[oi] ;B[ni] ;W[nh] ;B[li] ;W[mh] ;B[jn] ;W[kn] ;B[kk] ;W[gn] ;B[fo] ;W[il] ;B[ik] ;W[hk] ;B[ij] ;W[hj] ;B[jl] ;W[hl] ;B[ih] ;W[hi] ;B[jg] ;W[pf] ;B[og] ;W[of] ;B[qf] ;W[pg] ;B[qg] ;W[bo] ;B[bp] ;W[do] ;B[cp] ;W[cl] ;B[on] ;W[pc] ;B[pd] ;W[oc] ;B[nd] ;W[nc] ;B[qc] ;W[jc] ;B[kd] ;W[kc] ;B[pk] ;W[qk] ;B[pj] ;W[nk] ;B[mk] ;W[lf] ;B[le] ;W[kg] ;B[jf] ;W[lh] ;B[pm] ;W[qm] ;B[ro] ;W[rq] ;B[np] ;W[oo] ;B[qn] ;W[po] ;B[qi] ;W[rj] ;B[jm] ;W[ki]C[August 6 1954, 8:15am] ;B[nq] ;W[iq] ;B[ir] ;W[jp] ;B[kq] ;W[lr] ;B[no] ;W[nr] ;B[mr] ;W[or] ;B[mq] ;W[kp] ;B[kr] ;W[gc] ;B[ek] ;W[dk] ;B[gm] ;W[ks] ;B[jr] ;W[lp] ;B[ms] ;W[hm] ;B[fn] ;W[hn] ;B[ej] ;W[ii] ;B[kf] ;W[mf] ;B[ne] ;W[pi] ;B[ok] ;W[mj] ;B[nl] ;W[lj] ;B[lk] ;W[kj] ;B[ls] ;W[eb] ;B[db] ;W[ld] ;B[me] ;W[jd] ;B[ke] ;W[bn] ;B[bh] ;W[bi] ;B[bg] ;W[ec] ;B[dd] ;W[ap] ;B[aq] ;W[ao] ;B[bq] ;W[rn] ;B[nf] ;W[ng] ;B[ri] ;W[qb] ;B[rb] ;W[pb] ;B[gd] ;W[hd] ;B[ci] ;W[cj] ;B[di] ;W[bj] ;B[ge] ;W[gb] ;B[gg] ;W[eh] ;B[ff] ;W[fi] ;B[ra] ;W[da] ;B[ca] ;W[ea] ;B[cb] ;W[dm] ;B[df] ;W[eg] ;B[cg] ;W[jh] ;B[he] ;W[lm] ;B[id] ;W[hc] ;B[ns] ;W[mm] ;B[nm] ;W[os] ;B[op] ;W[pq] ;B[ei] ;W[fh] ;B[hh] ;W[ie] ;B[je] ;W[ic] ;B[pl] ;W[fj] ;B[fk] ;W[gl] ;B[fm] ;W[gh] ;B[hf] ;W[jj] ;B[jk] ;W[gq] ;B[gr] ;W[si] ;B[sh] ;W[sj] ;B[gk] ;W[gj] ;B[eo] ;W[dn] ;B[qa] ;W[pa] ;B[md] ;W[lc] ;B[ai] ;W[aj] ;B[ah] ;W[ph] ;B[pe] ;W[dh] ;B[fc] ;W[fb] ;B[fd] ;W[mo] ;B[if] ;W[mp] ;B[nn] ;W[ln])

[ntyllbtl] Deviation from asymptote

A few potentially useful functions for a calculator or numerical library, mostly within the theme of avoiding underflow, overflow, or loss of precision.

exp(x)-1 = expm1(x)
ln(x!) = log(x!) = log(gamma(x 1)) = lgamma(x 1)
1-cos(x)
1-sin(x)/x = 1-sinc(x)

erf(x)
1-erf(x) = erfc(x)
erfc(x)*exp(x^2) = erfcx(x)
1-erfcx(x)*x*sqrt(pi) = an even order power series that starts with 1/(2*x^2)

-i*erf(i*x) = erfi(x)
sqrt(pi)/2*exp(-x^2)*erfi(x) = F(x) Dawson function

And their inverses:

log(1 x) = log1p(x)

[qeysojwp] Wristwatch flashlight

Create a wristwatch with a small LED flashlight.  This should be easy, inspired by a small keychain flashlight.  To allow the watch to be worn on either arm, let the display read across the wrist, 90 degrees turned from typical watches.  The flashlight is aimed in the direction of 12 o'clock, if the watch has an analog clock face.

Brief online searches only found bulky watches with large, powerful lights.  Even small flashlights are very useful.

Or pocket watch.

[hgohmzih] Replication of the volcano

Responding to criticism (e.g., xkcd 1611) that the classic baking soda and vinegar volcano experiment is not really science: one the fundamental tenets of science is that it can be replicated.  The result does not depend on, say, the whims of a god or the character of the experimenter, which is how people believed the world worked before science.  Replicating the reaction of baking soda and vinegar, showing it behaves the same was as it did in previous experiments, the way as predicted by theory, is very much science.

[naoqfqdm] Clamped book

Consider the task of printing a multipage document which has very low likelihood of every being read in the future, some sort of archival application, or a backup copy.  One does not need anything as fancy as book binding, which produces something that can be read many times.  We are interested in providing a way of keeping the pages together, and of protecting the pages from external forces, like being folded or dropped.

Incidentally, a nice feature of unbound pages is that if the "book" ever needs to be read, and read a lot, the unbound pages can easily be passed through a sheet feed scanner.

Unbound pages in a box is the obvious first idea.  Slightly difficult in that we would like the size of the box to be precisely big enough to hold the pages and no larger.

Pages sandwiched between two sheets of stiff material, like book covers, but held together with a clamp instead of book binding.  Easiest idea, the clamp is something that wraps tightly all the way around, perhaps string or band.  Bolts connecting the covers on the outside of the pages, on all four corners.  Bolts through holes in the pages, most famously binders with three hole punched paper.  Most unorthodox: a single bolt through the center of each page.  This requires printing to avoid printing in the center of the page.

The sides of such a sandwich remain unprotected, but have mostly been fine for books, which suffer the same problem.

Because everything is tightly clamped into a rigid object, it resists shear forces, to which traditionally bound books are weak.

[wxnzzyds] Signed text to speech

Convert text to speech by an automated tool, but embed in the sound file a cryptographic signature, probably of the author of the speech.  No one else (without access to the private key) can produce exactly that sound file.  Perhaps encode the cryptographic signature in the pacing or pitch of the words.

Previously the reverse: forging someone else's voice.

[xpsszzyh] Outcome of previous similar decisions

A person or entity faces a decision.  Useful would be information about other people facing a similar decision in the past, which choices they made, and what the outcomes were.

So useful would be such information that there is incentive to conceal or obfuscate such information, by entities who have an interest in the decision being made in a certain way.  How much of that is going on?  What techniques are effective?  How can such disinformation be combatted?

Inspired by an proposition in an election: surely this has been tried before by someone else.

Previously, how would your life be different?

[cbdahxfo] Self-executing document

Consider a document, say HTML, which has embedded code, say Javascript, which runs to generate parts of the document.  Unlike Javascript in a typical webpage these days which can do things like have an event loop responding to input events or make further network calls, the embedded code can do neither of those.  It runs once and is done, generating a static content.  It is not an active document.

A straightforward application is a document with a text decompression engine built into it.  A document could have many sections (perhaps hierarchical) and sections might only get uncompressed on demand, or the browser could uncompress the whole thing all at once; it should make no difference.

Code could produce more code, which could be executed only when the user reads that section.

Slightly problematic is finite code can easily produce an infinitely long document.  If so, don't try to print the whole thing.  This feature could be useful for a teaching document to be able to produce unlimited random examples illustrating something.

While not strictly necessary, we prohibit the embedded code from making further network calls.  The document, with its embedded code, is entirely entirely self-contained once downloaded.  Once all the embedded code has run to completion (modulo infinite documents), the reader can be sure of having the whole thing in front of them.  This is a mental model of a document that is familiar to humans, like a finite book.  In contrast, web page with active and possibly networked content makes it impossible for a user to "have" or be sure to have read or experienced the whole thing.

(Large documents which are only fetched over the network on demand in portions are of course useful for devices with a small footprint, but not the subject of this post.)

Define a subset of Javascript limited to this functionality.  Design a way to detect that pages only use such functionality, or a way for pages to declare that they only use such functionality.

Friday, April 29, 2016

[hlvmqhqo] Small crowdsourced logic first

Previously, we mentioned a crowdsourced discussion forum moderated by automated natural language processing backed by a logic engine.  While running a country with it is the ultimate dream, start with something smaller.

Compose a novel or screenplay with snippets and ideas from a huge number of contributors.

[uwyrcwkf] Pushing the Trinity button

Pressing the button to detonate the Trinity atomic bomb must have been an interesting experience.  The theorists were pretty sure what was the worst (or best, if "big boom" was the goal) that could happen, but there remained the small possibility in people's minds that the explosion could be much more powerful than expected, perhaps even powerful enough to extinguish all life on earth.  The thought of possibility of doing that, in a single action, has probably happened exactly twice in human history: Trinity and then Ivy Mike, the first hydrogen bomb, 1000 times more powerful than previous atomic bombs.  I'm not sure if it'll ever happen again.

We can easily speculate several mechanisms that could have ended it all.  We now know these don't happen, but at the time, they didn't know.

A then-unknown exothermic chemical reaction involving nitrogen, oxygen, or the materials of the earth with such high activation energy that it could only be realized inside an atomic bomb.  However, once it starts, the exothermic reaction causes a chain reaction, destroying the atmosphere, or the planet.

Similarly, one could speculate a then-unknown nuclear reaction that causes a chain reaction with surrounding air or earth.  For example, nitrogen wasn't predicted to favorably undergo fission, but with enough neutron flux, perhaps it does, releasing more neutrons in the process.  Incidentally, the Castle Bravo H-bomb test did discover a then-unknown nuclear reaction involving lithium, causing it to explode with much more energy than expected.

Descending further, there could have been a then-unknown subatomic reaction that only occurs at high temperatures.

The general idea is, there is a limit to our knowledge of science at any given point in history.  Similar doomsday predictions were raised about RHIC and LHC, though I believe those objections were addressed by known science at the time (of cosmic rays).

Fictionally illustrate a doomsday reaction triggered by Trinity spreading through the world, against the backdrop of WWII having just ended in Europe and still raging in the Pacific.  Perhaps the chain reaction is slow moving.  Suddenly people become no longer concerned about the war in the face of imminent extinction.

[orolqvgw] Don't store credit card numbers

Online merchants should make it easy for customers not to store information such as credit card numbers with the store.  Those who provide this feature (unfeature) should be promoted.  Perhaps a special category of merchants who refuse to store the information.

Not storing the data protects against all-too-common data breach.  The shopping experience for the customer can remain equally smooth if the customer uses automatic form fill feature in the browser: websites should be designed to work well with autofill (they already mostly are)  and the merchant site can encourage using such a browser feature or extension.

The task of safeguarding data then falls on the customer, e.g., password protect browser autofill data and avoid keystroke loggers, but there is no longer a conflict of interest nor is there a single point of failure for many customers, an attractive target for hackers.

[tayhxctf] Amateurism at the Olympics

The modern Olympics (Pierre de Coubertin) were founded on an ideal of amateurism, an idea of getting people from all over the world together through their common love of athletics, then they go back to their non-athletic lives taking back with them the feeling of international brotherhood with an ultimate goal of world peace.

That ideal seems to have fallen by the wayside with both the increasing prevalence of professional athletes and international sports events being a political tool of nationalism and demonstrating superiority of one nation over another.  The idea of "represent your country" is inherently nationalist: contrast it to, "I don't see myself as an American; I see myself as a pole vaulter."

Maybe in the less major sports it still persists.

Do we need an event that returns to that ideal?

On one hand, heavily amateur dominated smaller events exist in droves (e.g., world pole vaulting convention).  International events are inherently expensive to travel to, so the money has to come from somewhere, so whoever is providing the money wants to know what's in it for them, e.g., if the state is providing the money, then it naturally becomes a nationalist tool.

On the other hand, international brotherhood might be a hopeless hippie dream: the forces, often political, that keep people and countries apart are much stronger than anything merely a joint event can bridge.  At such events in many participants is somewhat of a compartmentalized mentality: we will interact as fellow athletes, we might interact as fellow humans (most famously in the huge amount of sex that allegedly occurs) but we otherwise deliberately do nothing to build bridges between cultural and social differences: those topics are taboo, deliberately left unraised to temporarily pretend to get along.  (Inspired by dance events.)

[dhsezymy] Fake rulers

Consider a boutique business that constructs objects at sizes slightly different from their standard sizes.

Most interestingly, measuring tools.  Obviously usable for fraud, but perhaps other things.  (Jokes like in Amelie.)

Need to be careful about trademarks.

What kinds of things, especially measuring tools, do people take for granted that they are accurate, that no one would take the effort to go out and make a very realistic fake?  Inspired by a cheap wooden ruler.  More complicated measuring tools people will easily suspect are broken or miscalibrated, e.g., scales, thermometers, timers.

Under what situations could a fraudulent measurement be perpetrated then actually matter a lot?

[phgtdukx] Timed time zone

Set your device to be in a certain time zone for a specified time interval, the known length of your trip to a different time zone.

Or time zone by GPS.

[wtpmvisj] Safety as a political instrument

"Feeling safe" could be something people actually deeply care about, or it could simply by an effective political weapon to get what you want.  Only in the former can it be inverted to write effective horror.  We can measure how real or merely political the issue is by measuring its prevalence in horror entertainment.

[rfgcbfou] Kafkaesque

The world seems ready for a modern adaptation of the works or themes of Kafka.  Might be public domain.

[psjpszaz] Passwordless device encryption

A device is encrypted but does not require the user to input any password or PIN.  The key is also stored on the device.  At first I thought this is completely pointless: an adversary getting hold of the device can easily access both the key and the encrypted data.  But can see it has some limited benefits:

All the data on the device can quickly and securely be wiped by securely wiping just the key.  (Though the flip side is that accidental damage to the key will destroy all the data.  Redundancy of the key makes it more difficult to securely erase.)

The key could be stored separately on the device from the rest of the data, in storage that is difficult to extract.  This forces the adversary to go through the running phone to extract the data, which could be monitored or bandwidth limited and so forth.

[pkigvwol] Con artists

On one hand, society is hardened against con artists.

On the other hand, people judge so much that putting effort into modifying your external appearance and behavior, or broadly how people judge you, should be often effective.

Maybe the things people judge by are things that are extremely difficult to change, among them, the network of people a person knows and are known by.

The system is probably stacked heavily in favor of false negatives instead of false positives.  But then there is then the scam of leveraging that arbitrage: profiting off the fact that people don't trust.

Thursday, April 28, 2016

[rlwnpdcy] To war

A technologically advanced but seemingly peaceful fictional society transforms itself to a highly militarily capable one faster than a real one can be imagined doing.  The way people think changes, something that normally takes time.

Inspired by The Final Flight of the Osiris.

Then, even more unrealistically, it transforms back to peaceful.

[ubhjfyxs] Words for the hyperoperation hierarchy

tetrate
pentate
hexate
heptate
octate
enneate ennate (merging consecutive vowels) nonate (Latin creeps in, as with polygons: John Conway "Naming Polygons" in newsgroup geometry.pre-college)
decate
hendecate undecate
dodecate duodecate
tridecate triskaidecate
3 = triate trate
2 = biate bate duate diate date
1 = monoate monate unuate uniate unate

These are the most silly ways of saying add, multiply, and raise to a power.

tetration
pentation
hexation
heptation
octation
enneation ennation nonation
decation
hendecation undecation
dodecation duodecation
tridecation triskaidecation
3 = triation tration
2 = biation bation duation diation dation
1 = monoation monation unuation uniation unation

Tetration = tetra + iteration, yielding tetraration, but substituting rar = r because it is awkward for the special case of tetra only.

pentaration
hexaration
heptaration
octaration
ennearation ennaration nonaration
decaration
hendecaration undecaration
dodecaration duodecaration
tridecaration triskaidecaration
3 = triration
2 = biration duration diration
1 = monoration monaration unuration uniration unaration

Of course, tetration is enough.

[jiabppsm] Epsilon nought and tetration

It is curious that Cantor Normal Form for ordinal numbers seems to arbitrarily stop at exponentiation in the hyperoperation hierarchy and not include tetration or beyond.  The choice causes epsilon-nought to be the first ordinal not expressible with exponentiation.  However, if tetration were permitted, then

epsilon nought = (tetrate omega omega)

Does including tetration induce weird holes or duplications, perhaps around (tetrate (omega+1) omega) or (tetrate omega (omega+1))?  This could be similar to the difficulty of defining tetration for real second arguments.

Epsilon nought is supposedly useful for proofs using induction, so there is something deeper going on in the arbitrary choice to stop at exponentiation.

After including all operations in the hyperoperation hierarchy, one could define the first ordinal not accessible by an expression consisting of those operations.  More precisely, one could define an ordinal that is the limit of (hyper1 omega omega) (hyper2 omega omega) (hyper3 omega omega) (hyper4 omega omega) (hyper5 omega omega) ..., so the omega-th member of the hyperoperation hierarchy.

[jryeuysy] Mersenne tower

One rarely gets to write a "real" number as a tower of powers (as opposed to large numbers constructed solely for the sake of being large), so let us write the recently discovered Mersenne prime 2^74207281-1 as a short tower of 2s:

2^(74207281-very small)
2^2^26.145057410993628413
2^2^2^4.7084663330378790944
2^2^2^2^2.2352572139710255571
2^2^2^2^2^1.1604408537661861258
2^2^2^2^2^2^0.21467299217592807307

Or (tetrate 2 5.21467299217592807307) using tetration extended to real numbers by "linear" approximation.

Or, as a tower of 10s:

10^22338617.477665834124
10^10^7.3490562914116265715
10^10^10^0.8662315739486796570
(tetrate 10 2.8662315739486796570)

Each of those decimal numbers could be computed to millions of digits. There's a Procrustean feeling to this: Mersenne numbers are inherently related to powers of 2, but we are forcing this one to be a power of 10.

Given a number N, solve for X in N = (tetrate X X).  Analogous problem for self-exponentiation.

[cqejnfvs] A note about the Goldstein Theorem

The mapping from a number in hereditary base notation to an ordinal number with omegas always results in an expression for an ordinal number with terms joined by plus signs only (addition), never minus signs (subtraction), because hereditary base notation by construction only has pluses.  A sequence of such plus-sign-only expressions that is strictly decreasing will converge to zero in a finite number of steps (this was the meat of the proof of the theorem).

If minus signs were permitted, then the following sequence

omega, omega-1, omega-2, omega-3...

is strictly decreasing but would not reach zero in a finite number of steps.  Arguably "omega-1" is not even defined for ordinal numbers, though such an expression could have been formed by substitution starting from something other than hereditary representation:

Given a positive integer N, prove that the sequence

N, N-1, N-2, N-3...

will reach zero in a finite number of steps.

Wednesday, April 27, 2016

[mzihtlnd] Tetration is enough

Addition, multiplication, exponentiation, tetration:  The applications get sparser the further up one goes, so beyond tetration seems mostly unnecessary, except for specialized fields dealing with large numbers for the sake of being large.

[hzvqnqfc] Hereditary Mersenne

Write Mersenne prime numbers in hereditary base 2 notation (hereditary representation), because why not.  Creates a wavy line of exponentiation.

[uewlvzdn] Binder with plastic sleeves

A 3-ring binder with each paper page encased in a clear plastic sleeve seems to be a sturdy method of book binding, not requiring special tools or equipment.  (In contrast, putting three-hole punched paper directly into a binder is extremely fragile: almost analogous to the humorous write-only memory or write-many read-once memory.)

Of course, very expensive per page.

How long-lasting is it?  Potential issues: ink from the page transferring to the plastic sleeve.  Degradation of plastic sleeve.  Plastic becoming not clear.  Cracking or tearing around the binding holes on each sleeve.

Not available in sizes other than letter paper.

Tuesday, April 26, 2016

[qfvmgvos] Extremely long scale numbers

Recursive construction of large numbers:

A0 = nine hundred ninety nine = 999
A0+1 = thousand = 10^3 = 10^(3*1) = 10^(3*2^0)
A1 = A0 thousand A0 = nine hundred ninety nine thousand nine hundred ninety nine = 999,999
A1+1 = million = 10^6 =  10^(3*2) = 10^(3*2^1)
A2 = A1 million A1 = nine hundred ninety nine thousand nine hundred ninety nine million nine hundred ninety nine thousand nine hundred ninety nine = 999,999,999,999
A2+1 = billion = 10^12 = 10^(3*4) = 10^(3*2^2)
A3 = A2 billion A2 = 999 thousand 999 million 999 thousand 999 billion 999 thousand 999 million 999 thousand 999 = 999,999,999,999,999,999,999,999
A3+1 = trillion = 10^24 = 10^(3*8) = 10^(3*2^3)
A4 = A3 trillion A3
A4+1 = quadrillion = 10^48 = 10^(3*16) = 10^(3*2^4)
A5 = A4 quadrillion A4
A5+1 = quintillion = 10^96 = 10^(3*32) = 10^(3*2^5)
sextillion = 10^192 = 10^(3*64) = 10^(3*2^6)
septillion = 10^384 = 10^(3*128) = 10^(3*2^7)
octillion = 10^768 = 10^(3*256) = 10^(3*2^8)
nonillion = 10^1536 = 10^(3*512) = 10^(3*2^9)
decillion = 10^3072 = 10^(3*1024) = 10^(3*2^10)
vigintillion = 10^3145728 = 10^(3*1048576) = 10^(3*2^20)

Coincides with American short scale up to 999 million 999 thousand 999 = 10^9-1.  Coincides with British long scale up to 999 thousand 999 billion 999 thousand 999 million 999 thousand 999 = 10^18-1.

I was tempted to introduce a made up suffix like -zillion, e.g., mizillion, bazillion, trizillion..., to avoid redefining existing words, but since there already exists confusion between the American and British scales, I felt there was no harm in adding more.

The key feature is that very large numbers can be expressed while introducing new vocabulary much slower, logarithmically slower, than the traditional method.  The Latin prefixes conveniently line up with the exponent of the power of 2, inspired by the British scale.  (It was also possible to have a construction building from 99 hundred 99 + 1 = thousand, but it does not line up with Latin so well.)

Create a program to convert to and from words and values.  It might be necessary to use the word "zero" as a placeholder to avoid ambiguity.  (Or, prove that such placeholders are not necessary.)  Try the program on some large Mersenne primes.

There's a sort of middle-endian feeling to it, as the most important word that determines the size of the number is embedded somewhere in the middle.

Because of the tree like structure, it might be the basis for steganographically encoding large numbers, e.g., cryptographic keys, as parse trees of sentences with word substitution.  Perhaps use a base other than 10, maybe mixed radix.

Also consider Japanese numerals.

Monday, April 25, 2016

[yjogsatv] Japanese days of the week

The Japanese abbreviations for the days of the week, 月 火 水 木 金 土 日, are more compact than their English counterparts, Mon Tue Wed Thu Fri Sat Sun.

The Unicode code points (in decimal) are 26376 28779 27700 26408 37329 22303 26085.

Are their any languages for which the first letters of the names of the days of the week are distinct?

[qqzihsax] Half turn Rubik's

A Rubik's cube limited only to half turns is entertainingly difficult.

[rxvquuuu] Monochromatic supercube

Consider a Rubik's cube with all white faces, but with arrows drawn on each face, with all arrows facing the same direction on each face, so a supercube.  How difficult is this to solve?  It might depend on the pattern of arrow directions between the faces.  How many distinct ways are there to draw an edge-aligned arrow on each of the six faces of a cube?

[fzgcaugq] Noncyclic De Bruijn

The traditional De Bruijn sequence is cyclic: certain combinations span the break between the end and the beginning.  The standard method to construct a non-cyclic De Bruijn sequence is to copy and append the first few digits from the beginnning onto the end (usually some zeroes).  Can this be improved?  Are their shorter sequences that cover all combinations, not allowing cycling from the end to the beginning?

Also De Bruijn torus: can we improve over copying the entire left and top sides to the right and bottom?

[cvejwwrf] Immune from invasion

In the olden days, if one country thought another country was weak, they would invade (and possibly genocide).  (Inspired by Lebensraum.)  This created incentive for countries to maintain some sort of a reasonably functioning, economically productive state.  (Unlike the collapse of the western Roman empire.)

Nowadays, if a country can field a nuclear arsenal, they can retaliate against invasion with such devastating force that no one will dare invade.  Therefore, there is no longer as much incentive to maintain a reasonably functioning state.

Is this logic true?  Are nuclear weapons unique and unprecedented in the history of military warfare in their ability to provide immunity from invasion?

Maintaining a nuclear arsenal does require a reasonably functioning state.

If a state is functioning poorly, even without invasion it may fall to internal forces of regime change, so the incentive to maintain a reasonably functioning state still exists even in a nuclear armed power.  (E.g., regime change in Soviet Union.)  Civil war could have external countries supporting the rebels.  Is an external country supporting and winning a rebellion functionally equivalent to invasion?  One could imagine the installed puppet government committing acts like genocide to benefit that external country that supported the rebellion.

If a nuclear armed government is facing a rebellion supported by an external country, will they use their nuclear weapons against the external country?  Should they?

Is the incentive to maintain a reasonably functioning state even good?  One could imagine a state using its nuclear umbrella to allow its citizenry to live peaceful and happy, albeit technologically backward and less economically productive, lives.  In contrast, in the past, a "reasonably functioning state" probably meant exactly one thing, "able to field an army", which is not necessarily good for the country or for human civilization as a whole.

Military alliances between nuclear and non-nuclear armed powers also cause weird effects.  The non-nuclear ally must accede to the desires of the nuclear ally or risk being expelled from the alliance.  Meanwhile, the non-nuclear ally gains the immunity from invasion accorded to nuclear armed powers.

[ijxatmmn] Women attracted to money

Stereotypically, women are attracted to rich men.  Women also have less earning power than men (modulo the difficulties of exactly comparing earning power).

The traditional narrative has the causality in the following direction: because women face institutional barriers in earning lots of money, they must seek out men with money.

However, we could hypothesize a different mechanism: in a hypothetical society in which women do not face barriers in earning lots of money, they have less incentive to seek out men.  This will result in less couples, less children, population decline, and the society will implode on itself, resulting in either extinction or change in society.  Therefore, only societies that place barriers on women from making money (or more broadly, create incentives for coupling) will survive: kind of a social Darwinist argument applied to societies competing against each other instead of individuals competing against each other.  This hypothesis does seem to be supported by data that increasing education for women (and thus increasing their earning power) correlates with a declining birth rate, and more egalitarian societies having lower birth rates.

There are some leaps of logic in the argument:

The biological imperative to procreate is pretty powerful.  We have not described any force powerful enough to override the imperative to explain declining birth rates.

Regardless of their own earning power, women could still continue to be attracted to rich men, because, all other things being equal, more money is more better.  Therefore, whatever psychological mechanisms that program a woman's ideas of what she finds attractive could still continue to operate in more egalitarian societies, and still drive women to couple.  We have not described what those mechanisms are and why they should stop operating.

We revisit another aspect of this model.  If men's attractiveness in the eyes of women is determined by their wealth, then the biological imperative to procreate will incentivize men to earn more money, so to be more economically productive.  A more productive society will again win Darwinistically over one which is less productive.  Do more egalitarian societies see less productivity in men?  Is the loss of their productivity offset by the increased productivity in women?

I strongly suspect there is still much more going on, including game theory.

[idydqxzf] Rubik's cube steganography

A 3x3 Rubik's cube provides a way of encoding 65 bits, though the problem of mapping cube states to numbers, especially of mapping them one-to-one, is left unsolved.  Like shuffling a deck of cards, it provides a convenient way of generating 65 bits of entropy, assuming hand scrambles can be trusted.

It is not too suspicious to be found carrying a scrambled Rubik's cube.  Carrying two identically scrambled Rubik's cube (a backup key) might be suspicious, but the nature of the backup could be concealed by (say) applying an easily reversed checkerboard algorithm to it.  (Creating two identically scrambled cubes is analogous to solving a cube.)  Store the cubes in boxes so they do not get accidentally turned.

A supercube (picture cube) provides exactly 11 bits more, or 76 bits.

4x4 cube 152 bits. 5x5 cube 247 bits. 6x6 cube 385 bits (but almost 386).

Megaminx 225 bits. Gigaminx 875 bits. Teraminx 1903 bits. Petaminx 3310 bits.

Previously, code for computing the number of combinations.

[vcppbmdn] Rubik's cube combinations

We implement in Haskell the formulae at http://www.speedcubing.com/chris/cubecombos.html to compute the number of combinations of a NxN Rubik's cube, as well as a supercube (for which center facet orientation matters) and a super-supercube (also called a "real" cube, for which inner cubie orientations also matter) variations.

import Math.Combinatorics.Exact.Factorial(factorial);

div_exact :: Integer -> Integer -> Integer;
div_exact x y = case divMod x y of {
(q,0) -> q;
_ -> error "division had a remainder";
};

common :: Integer -> Integer -> Integer -> Integer;
common i den_base n = let {
e1 :: Integer;
e1 = div (n*n - 2*n) 4;
e2 :: Integer;
e2 = div ((n-2)^2) 4;
numerator :: Integer;
numerator = (24 * 2^i * factorial 12)^(mod n 2) * factorial 7 * 3^6 * (factorial 24)^e1;
denominator :: Integer;
denominator = den_base ^ e2;
} in div_exact numerator denominator;

-- https://oeis.org/A075152
cube :: Integer -> Integer;
cube = common 10 ((factorial 4)^6);

-- https://oeis.org/A080660
supercube :: Integer -> Integer;
supercube = common 21 2;

-- https://oeis.org/A080659
super_supercube :: Integer -> Integer;
super_supercube n = let {
e1 :: Integer;
e1 = div_exact (n^3-4*n+(mod n 2)*(12 - 9*n)) 24;
e2 :: Integer;
e2 = div (n-2) 2 + mod n 2;
e4 :: Integer;
e4 = mod n 2 * div n 2;
} in (div_exact (factorial 24) 2)^e1 * 24^e2 * (factorial 7 * 3^6)^(div n 2) * (factorial 12 * 2^21)^e4;

Incidentally, the output numbers factor easily. The largest prime factor in them is 23. One could do the calculations over a factor base of primes from 2 to 23 to get the output directly in compact factored form.

Next, we consider the Megaminx, and higher odd-order variants (so not Flowerminx / Kilominx):

-- http://michael-gottlieb.blogspot.com/2008/05/number-of-positions-of-generalized.html
-- n=1 megaminx; n=2 gigaminx; etc.
megaminx :: Integer -> Integer;
megaminx n = div_exact (factorial 30 * factorial 20 * (factorial 60)^(n^2-1) * (factorial 5)^(12*n) * 2^28 * 3^19) ((factorial 5)^(12*n^2) * 2^n);

Full Haskell source code.

Wednesday, April 20, 2016

[wwsnjkib] Asshole

"Asshole" describes a relationship, not a person.  The relationship between the describer and the described, probably contempt.

[nujwkgbz] X street in X

Enumerate instances of where there is a street that has the same name as the city in which it is located.  More interestingly, trace the history of why that street got the very special name.  Sometimes, perhaps often, it is not the main street of the city.

[iiucvwtg] Two knights versus promoted pawn

Make the two knights versus pawn chess endgame more difficult by requiring that, at checkmate, the pawn must have promoted.

[tcbskdhn] How not to

"How to" is important to document, but also important is to document failures, providing bounds on how far one can deviate from the instructions.  Anecdotes of failures can be crowd sourced.

[bgdnnpfy] Twisted and evil

Some alternate version of Star Wars in which the complex nature of good and evil are explored:

Luke: But you said Darth Vader was twisted and evil!
Obi-wan: Many of the truths we cling to depend greatly on our point of view.
Luke: Fuck you, Ben.

[ogcqfppx] Easy access to paraboloids

When making any bowl-shaped object, e.g., tableware, choose a paraboloid (likely truncated by a plane) as the shape unless there is a good reason otherwise.

Easy access shapes able to concentrate or emit parallel rays might be useful for education and tinkering.

Maybe there's a danger of shiny objects catching the sun a just the right angle and setting things on fire.  A nanny state might ban paraboloids for this reason, though the conspiracy theorists would theorize that the government doesn't want to make it easy for the populace to build radio dishes.

[wkqkumle] De Bruijn style music

Create a song which has within it all (say) 4 note songs.  A De Bruijn sequence doesn't quite work because scale transpositions can be considered equivalent.  Cyclic is OK: the song repeats.

Simplifications / constraints: Limit to two octaves of a small scale, e.g., pentatonic.  We don't care about covering 4 note songs with a range greater than an octave, or jumps larger than a fifth, or tritone jumps.  Limit rhythm in some way, the most obvious being only quarter notes, though that might be too boring.

Inspired by change ringing .

[ppzkvtnw] The Shitshow

A TV show about the dysfunctional behind-the-scenes production of a TV show.  Inspired by stories of dysfunction behind the scenes of real TV shows.

Same idea as 30 Rock.

[czcebacy] Bending the body variously

People try many different chairs, even standing desks, but all fail due to the fact that the body does not like to maintain any one position for an extended period of time.  Even lying down becomes uncomfortable after a while.

Create a motorized chair-ish device that continually moves the body to different configurations and orientations, perhaps from lying to standing.  If it is for working at say a computer, the screen and input devices also need to move.  Mouse must be magnetically attached to mousepad, or use a trackball.  Because the arms may move around, the keyboard needs to be split.

[tqyvaumr] Reflecting CPU instructions

Provide a system call or library function which gives the number of CPU instructions this thread has executed, independent of CPU time or wall clock time.

Perhaps (probably) approximate: maybe the OS tracks CPU time per thread and returns that number multiplied by a factor.

Get a heterogenous collection of computers to all do the same amount of work, perhaps for benchmarking.

[pcpzbfob] Lexicographic numbers

Given a set of numbers, strictly speaking, digit sequences because 01 and 1 are distinct, sort them lexicographically.  Unfortunately, in certain places, one cannot insert a new number.

It is impossible to insert anything before 0.  It is impossible to insert anything between 1 and 10.

We assume these numbers are keys to a map-like data structure, and we would always like to be able to insert anywhere.  Real numbers would work, except concrete implementations like IEEE 754 do have values which are minimum and also have pairs of numbers with nothing in between.

Fix this by considering digit sequences contrained to end in 5.

Decreasing sequence: 5 > 25 > 15 > 05 > 025 > 015 > 005 ...
Increasing sequence: 5 < 85 < 95 < 985 < 995 < 9985 ...

Equivalently, assume that every number invisibly has a 5 appended to it.  We can easily insert things before 0:  000 < 001 < 002 < 00 < 01 < 02 < 0.  This part resembles women's clothing sizes, or machined part sizes, with longer strings of zeroes meaning smaller.

Confusingly, 10 < 1.  Numbers sort like this: 10, 11, 12, 13, 14, 1, 15, 16.  One can see there are plenty of things that can be inserted between 10 and 1.  In the close neighborhood of 1 is 14 < 145 < 149 < 1 < 1502 < 150 < 152 < 15.  We can also insert things before 10.  0 < 05 < 06 < 09 < 100 < 104 < 10.

The empty string curiously sorts between 4 and 5, though perhaps it should be forbidden.

The invisible 5 at the end sometimes acts like a digit whose value is in between 4 and 5, because X4999999... < X < X5000000...

Compute the shortest number between two given numbers, or smaller or larger than a given number.  If there are many such shortest numbers, determine the middle one.  1 "" 7 8 9 97 98 99 997 998 999 ...  But when counting up, it makes more sense to compute the least shortest number: 1 "" 5 6 7 8 9 95 96 97 98 99 995 996 997 998 999 ...

I had a few false starts before discovering this scheme and am not completely convinced the scheme doesn't have problems.

The idea could be extended to sorting words with letters, even compound words with spaces in which the space character lexicographically sorts before a.  Let M be the invisibly appended letter, analogous to 5.

For binary, we need at least two invisible appended digits, 01 or 10.  For balanced ternary, I think the invisible digit could elegantly be 0.

For the purpose of creating numbers which always have another number in between, and larger, and smaller, arbitrary precision real numbers, including negative numbers and arbitrary precision after the decimal point, would work just as well and be less confusing.  Though sorting seems harder, needing to first locate the decimal point.

[fqmwiugx] Email address

Typing an email address, for whatever reason, is awkward, requiring an interface with lots of buttons, or some other awkwardness like T9 input (with symbols).  Onscreen keyboards and handwriting recognition (by human or by machine) are similarly awkward.

Instead of typing it in, let an interface be able to accept it by scanning a QR code or reading NFC.  This of course requires the user to carry a physical token.  Maybe tattoo.  Cameras are more compact than keyboards.

The at sign @ annoyingly is not one of the 45 special alphanumeric characters that QR encodes efficiently, though it is not that big of a deal to encode 1 character with a byte encoding.  Perhaps modify email clients (or more ambitiously, the email standard, or even more ambitiously, create a new standard entirely) that permits one of the 9 other punctuation marks as a separator.  I advocate Space.

A physical token can deliver more data than a human can easily memorize, so can also usefully provide things like a public key or public key fingerprint.

[tqucxexi] Creating people with something to lose

A welfare state provides assistance to the poor.  This potentially gives the provider of the assistance, namely the government, tremendous power to control people through the threat of withholding that assistance, and such absolute power will corrupt absolutely.

Certain forms of assistance, for example, minimum wage laws, are difficult for the government to withhold to particular individuals.  Other forms of assistance, for example, the government directly providing money, cause less distortion in the economy than minimum wage laws, but are easy for the government to withhold.

One possible workaround for the government having too much power: Instead of the government providing money directly, let it be some heterogenous collection of independent assistance providers.  If one provider corruptly refuses assistance to someone, they can turn to another provider.  There's the tricky problem of people taking from multiple providers, which if the government were the sole provider, they can ban multiple identities.  Instead of efficiently providing money as assistance, they can provide material assistance of things it does not make sense to take more than one of, e.g., food.

If this heterogenous collection of providers gets is funds from private donations, then the model precisely captures the privatized welfare system favored by conservatives.  It has flaws, most basically people want to donate to help One Of Us, and not One Of Them.

The original inspiration was crimes committed by people at the bottom of the social pyramid who have nothing to lose.  Welfare policies are often directed at decreasing such crime.  On one hand, it seems sinister to be altering behavior by threatening to withhold welfare assistance, treating people like puppets.  On the other hand, will welfare assistance with guarantees it cannot be withheld be effective in changing behavior, or will it continue to perpetuate a class of people with nothing to lose?

More generally, when does "good" monoculture happen?  "Good" meaning people don't see others as One Of Them (and then committing crimes against them).

[kwntcebt] Cube mate in 3

A Rubik's cube that is a small number of moves, say 3, from solved makes for a nice puzzle.  The player is challenged to find the optimal solution rather than applying a generic solving method.  Similar in spirit to chess mate in N problems.

Ideas on how to set up the puzzle:  The obvious method, make 3 random moves while looking, fails because it is too easy to remember the scramble you did.

Scramble 3 moves behind your back, turning the cube a lot between turns.

Have a friend do it where you can't see.

Build a machine to do it, concealed behind a screen.

Computer algorithm to get to the puzzle state by a roundabout way: first find a short sequence to a random state (utilizing God's Number), then solve for a short sequence (via Kociemba algorithm or similar iterative deepening) from that random state to the target 3-move-scrambled state.  Hopefully the short sequence does not go through 0- 1- or 2-move scrambled states.

Rubik's Touch (if it could be modified) could offer such puzzles.  It has the advantage of being easily able to be reset to the puzzle start state.

Deep cut puzzles change a lot even in a single move, so would provide challenging short puzzles.

A small number of moves away from the cross, on some side, might be a useful puzzle to practice speedsolving.

[fvjoblmc] Robotic pets

On one hand, with computers getting more powerful, it seems like soon (if not already) we can create robots which can handle all the complexities of the real world in a reasonable if someone stupid way.

On the other hand, mechanical engineering has not advanced as fast as computer science (though this is a comparison between apples and oranges).

Can a human learn to love a machine as they would a biological pet?  Perhaps we still need some more advances in fluffy and squishy mechanical engineering.

Robotic pets of course have advantages over biological ones.

From there, it seems only a short hop (possibly over the uncanny valley) to robotic children as depicted in Spielberg's A.I. Artificial Intelligence.

Robotic versions of really stupid animals, e.g., fish, turtle, insects, seem doable now.  Perhaps put the computer outside the robot and control it wirelessly.  Though we still need to program the effect of the pet learning to trust its owner, which provides the great pleasure of owning a pet.

[kxjcihjt] What is real?

Reality is merely the model which provides the best predictions, though "best" is fuzzy: most accurate and most precise.

Inspired by the question, are fields (in physics, e.g., electric field and magnetic field) real, or are they merely mathematical tools to calculate more real effects like motion?  By this definition, they are definitely real.

[zsiutopq] Most expensive bridge

Divide the inflation adjusted cost of a bridge by the number of crossings per day.  What are some expensive, rarely used bridges?

Of course, this is not a fair statistic because we want the opportunity cost of the next best crossing.

Inspired by the Mackinac Bridge which does not seem to connect any major metropolises.

[vnuugcwh] Human chromatography

Gather a bunch of humans.  Apply some sort of stress.  Watch them separate out by... something.

Tuesday, April 19, 2016

[vjqzxiau] Change ringing

Change ringing with the bells ringing in sequence (as is traditionally done) is inefficient: a De Bruijn sequence can accomplish all permutations faster.

Instead of one bell at a time, ringing them as chords allows hearing every possible mixing.  Every possible n-chord sequence also seems doable for small n.

Neither of these work so well with the physical constraints on how often a single bell can be rung.  Both long gaps and rapid succession are bad.

[zsrwafja] My God it's full of lies

Parody of the line from the novelization of 2001: A Space Odyssey.

[otuodiyg] Adjusting the number of failed password attempts

For authentication systems that do something drastic after a number of consecutive failed password attempts (e.g., iPhone wipes the device), let the threshold number be adjustable higher by the user.  It could also be automatically adjusted based on the length of the password.  Should the threshold number be linear or exponential in the length?

Inspired by needing to type a long password on an flaky input device which often dropped keystrokes.

[zrkjrxzb] Quality by not quality

An environment which does not put emphasis on creating high quality may paradoxically create higher quality than one which does, by the mechanism that the lack of emphasis on quality creates a safe environment to make mistakes, and then people learn and improve through making mistakes.

Monday, April 18, 2016

[gkszsqre] Standard Model

Chapter 1: some pretty charts organizing the quarks, leptons, neutrinos, and force carriers.

Chapter 2: Multi page formula of the Standard Model Lagrangian.

It's a little steep between chapters 1 and 2.

T-shirt: What part of (insert equation from http://nuclear.ucdavis.edu/~tgutierr/files/stmL1.html, compiled from Diagrammatica by Veltman ) do you not understand?  Or, find the sign error.

[okaremlt] Always count in base 100

When numbering things on a computer, e.g. files, always start at 00 or 01 and not 0 or 1 so that things can easily be lexicographically sorted until 99.  "Usually" you don't have over 99 things, but you often have over 9.

Alternatively, 8 is followed by 900.

[jprwidsh] Wishful thinking software ecosystem

All the software bundled with a computer system is perfect and bug-free, so there is no need for a software update mechanism.

The bundled software provides everything a user could ever want to do with the system, so there is no need for a mechanism for distribution of additional software, e.g., app store.

On one hand, these are silly, mocking deficiencies of many old platforms.

On the other hand, they are within the realm of imagination.  Software engineering might someday produce perfect software.  The bundled software could provide enough components for a user to easily build anything further wanted.

[hencdqdu] Abusing a biometric database

Given access to a large biometric database, it becomes a lot easier to find people who look alike, where "look" means the features stored in the database, which could include appearance but other features too.  This capability can almost certainly be abused, which is worrying, because only large powerful organizations can field or have access to large biometric databases.

Hire someone who looks like someone else to commit a crime, to thwart eyewitness identification.

[bliqpkxk] 8 to the bar

Hypothesize that in the phrase "eight to the bar", the "bar" is a dance bar of 8 beats, and not a musical bar of typically 4 beats.  (The 8 counts to a bar is why dancers count off 5 6 7 8 at the beginning while musicians count off 1 2 3 4, or "ah 1, ah 2, ah 1 2 3 4".)

If a dancer asks for 8 to the bar, e.g., "Beat me daddy, eight to the bar" (Andrews Sisters), then the dancer is asking for 8 strong beats to the dance bar, so a strong beat on every quarter note.  This contrasts to just 4 strong beats in a dance bar, a strong beat on every half note.  This distinction is the same as the "4 feel" and "2 feel" known to jazz drummers and rhythm sections.

A 4 feel is famously the style of swing music, with the bassist playing a note on every beat, often a walking bass line.  A 2 feel is famously the style of blues and rock 'n' roll.  (There are of course, many exceptions.)  A dancer asking for 8 to the means asking for a swing song as opposed to a blues or rock song.

This YouTube video, at 2'25", illustrates the difference between 2 feel and 4 feel.

[nmrjialj] Shoe throwing

Create a sport, perhaps similar in style to a shooting range, in which the goal is to throw your shoe to hit a target.  Inspired by the Bush shoeing incident.  A populace that is good at this is kind of like the sword of Damocles, in a symbolic way.

Some sort of large conveyor belt that returns your thrown shoe back to you.

[arhfweaq] Standardized cookie formats

For the common use cases of cookies, create standards of cookie data formats the websites can conform to (and announce their conformance) so that users can examine and interpret their cookies.

[pygitqnl] Density of containered foods

Foods sold in a watertight container, e.g., bottle, can have their mass easily measured (weight of container before and after emptying) and their volume easily measured (after emptying, refill with water).  Calculate and publish densities (because it's fun?).

Requires a kitchen scale and a graduated cylinder.

[cjkhaezz] Kyu dan threshold

Kyu and dan rankings in go 囲碁 almost act like negative and positive numbers.  If it were exactly like numbers, then calculating the stone handicap by subtraction would be easy.

In order for them to exactly act like numbers, there would have to be a 0 kyu rank that is equivalent to a 0 dan rank.  1 kyu and 1 dan would be separated by 2 ranks.  This would not be too strange: an extra large barrier between kyu and dan ranks, signifying advancement from student to master.

The way it currently works (I think) is that 1 kyu is followed by 1 dan; there is no 0.  Equivalently; 0 kyu = 1 dan and 0 dan = 1 kyu.  The crossover occurs at 0.5 kyu = 0.5 dan, if fractional ranks existed.

Another way it could work (but doesn't) is for 1 kyu = 1 dan, essentially zero being "spelled" 1.

[cfsleqpw] Resolving EPR with wormholes

Special relativity forbids information traveling faster than the speed of light.  General relativity does not.  Therefore, resolve the Einstein-Podolsky-Rosen paradox by stringing a wormhole between two entangled particles, allowing them to communicate as fast as they need.  The size of the wormhole is smaller than we can currently observe.

It is unsettling to think of space as like swiss cheese filled with lots of tiny holes connecting different points superluminally, or of space being crisscrossed by lots of tiny wormhole tunnels, but everything else in quantum mechanics -- and general relativity -- is unsettling also.  Most wormholes will be short: entangled particles can't travel very far before hitting something that observes one of them, at which point communication happens through the wormhole, and the wormhole becomes no longer necessary, so we assume it dissipates by some unknown mechanism.  Or, if there are entangled particles flying around for long distances in a nearly perfect vacuum, then, because it is a vacuum, there's nothing in the region that will "care" that there's a long wormhole in the area.

How small can wormholes be?  Is there a relationship between the size of a wormhole and how much, or how quickly, information may be transmitted through it?  What interaction would such tiny wormholes have with surrounding matter?  Currently there exists no theory of quantum gravity, but in the future, there may be an experimentally supported one, which in turn could disprove this theory.

Holding the mouth of a wormhole open requires negative matter.  Future subatomic particle experiments may disprove whether entangleable particles are composed in part of negative matter, in a way similar to how mesons are composed of both matter and antimatter.

Inspired by the Conway Kochen Free Will Theorem, which makes the assumption of no superluminal communication between particles.

[ajkaflia] Compress recursive text

Consider using mathematically generated text as (one of) the test cases for data compression methods.  For example:

Look and say sequence: 1 11 21 1211 111221 312211 13112221 1113213211 ...
Dragon curve: RRLRRLLRRRLLRLL...

The sequences have a lot of repetition, but do not repeat in any obvious periodic way, which is often a characteristic of data one wants to compress.

A quick test on 1 GB of Dragon Curve found that bzip2 compressed much better than gzip or xz but was also much slower.

Also human genome.

Sunday, April 17, 2016

[sqnzlbyw] Three button laser mouse

Missing in the market landscape is a simple corded laser mouse.  We prefer corded (a.k.a. wired, so not wireless) to not have to worry about running out of battery, and to decrease weight.  Laser to avoid the bright red LED.  Simple 2-button or 2-button-with-scroll-wheel to avoid accidentally hitting one of possibly many side buttons causing unintended effects.  Laser mice seem to be targeted at gamers and have a zillion extra buttons.  Also, one reason for using an (infrared) laser mouse instead of a bright red optical LED mouse is to avoid casting distracting light from the mouse to the surroundings when using it in a dark environment.  Gaming mice often also have a zillion lights on the top side, negating the benefit of avoiding the LED.

[hoskxrso] Menger building

The Menger sponge seemingly cries out to be built as a building: courtyards, windows overlooking courtyards, vertical shafts to permit natural light to get to internal areas.

[slmywigd] Wikipedia history report

On a subject that interests you, examine the full history of all edits to the article.  Is there an interesting narrative, perhaps of the article being systematically and persistently made worse?

The opposite of a report in which one is forbidden from citing Wikipedia: one can only cite Wikipedia.

[iqzzgvod] How is an icosahedron like an even permutation?

Create a geometric demonstration of how the rotations of an icosahedron or dodecahedron align with the even permutations of 5 objects, in particular the group action.

My guess is there is no good demonstration: that the two groups are isomorphic is just coincidence, vaguely an instance of the Strong Law of Small Numbers: there are not enough small finite groups to meet the demands made of them.  The icosahedral group had to factor into some collection of small finite simple groups, and A5 is where it just happened to land.

Why is a raven like a writing desk?  Lewis Carroll was a mathematician.

[csclnykm] Beans Don't Talk

By Conway, based on Beanstalk by Isbell, is an elegant game.  Two moves: 3n+1 and 3n-1, then automatically dividing by 2 until it is odd.  Getting to 1 wins.  The major open question is whether there are starting numbers from which neither player can force a win.

How far out has it been verified?  What is the longest known win?  What are some strategies that don't involve a giant look up table?  Probably factorization.

Reminiscent of Collatz conjecture.

[evlqigce] Konane

When playing konane on a checkerboard, place the light pieces in the dark squares and vice versa so that they have good contrast.

An odd by odd board starts with more pieces for one player.

What happens if all the pieces are identical?  Impartial konane, not a partizan game.  Both players may move any of the pieces.  Resembles peg solitaire.

Easily generalizable to more dimensions or other graphs with a notion of three nodes in a straight line.

[ymtwwbli] Online chess opening research

As you play someone in online chess, let the UI make available both yours and the opponent's previous games and moves played from the current position, perhaps annotated with computer analysis.

Both players can see both players' past games, so there is no advantage in information.  You know, they know you know, you know they know you know, etc. (common knowledge).

Amateurs can mimic the opening preparation done by professionals, though not have to memorize it.

[sjegcxoq] Avatars for online chess

Being able to design an avatar for online chess might be enjoyable for some players, even though it seems silly or extraneous.  The UI will probably keep it possible to turn off having to view your opponent's avatar, but a player might benefit from being able to see his or her own avatar play the moves, a way of fantastically being someone else.

More ambitious is for one's computer to do motion capture to animate one's avatar at the virtual board.

[yokhizjo] Chess960 opening selector

Let an online Chess960 interface preferentially choose initial positions that both players have not played, or played least frequently.  There remains a tricky detail of balancing the two players concerns: probably minimize the maximum of the two frequencies.

A player could game the system by being able to predict in advance what initial position will be chosen and prepare for it, negating the benefit of Chess960.  Need to have some randomness so that the optimal initial position is not always chosen.

Offer special recognition to players who have played every initial position with both colors, and have won from every initial position.

[uhgfhmup] Solar powered buoy

Intriguing is a computer mounted in a buoy floating in international waters (terra nullius), so not subject to the laws of any country on what it may compute, most famously laws about copyright.  As computers get more powerful, it may begin to resemble a person not subject to any laws.

Use solar power.  Or maybe wind or wave or tide.

How can it communicate with land, especially if it needs to do so surreptitiously?

How can it defend itself from being discovered and destroyed?  It might begin to resemble an autonomous submarine.

Of course, nature makes the ocean already a harsh place to try to survive, e.g., storms.

Previously, a satellite.  Space is also terra nullius.

[nhmbkbcx] Chaotically moving dance floor

Create a floor subdivided into many intersecting discs.  Each disc turns sometimes and stops sometimes to allow other discs to turn.  Cuts in one disc will need to line up properly to allow an intersecting disc to turn.

The Geranium Puzzle illustrates the concept.

Inspired by a club with a slowly rotating dance floor, a single disc.  Multiple slowly rotating discs might make more mixing happen.  Of course, stuff getting caught in the cracks will be a problem.

[gboweiiv] Cave of the crystals and Climate change

Exploring the Cave of the Crystals required a special refrigerated suit, as humans cannot survive in high humidity and high (but not melting or burning) temperatures.

Global warming is predicting to bring about conditions requiring similar suits in certain parts of the world (Pal and Eltahir, "Future temperature in southwest Asia projected to exceed a threshold for human adaptability").

[zhnknjpl] Visible premove

Create an online chess interface in which premove is permitted, but the opponent can see the premove that you are planning to make.

Making visible more information, having less hidden information, will hopefully yield higher quality games.

[vwysedoo] Dubbing

A technology that I am surprised that doesn't exist yet is altering one person's voice to match another's.  Both people read the same calibration text, or even different texts which both cover most of the phonemes, and then it seems a simple matter to map over the phonemes.

Dub the audio track of a movie from one language to another, preserving the original actor's voice.  The intermediate steps (not done automatically) include translation, then a stand-in voice actor speaking the translation, then the audio of the translation being adjusted from the voice of voice actor to the original actor.

Of course, such technology makes it difficult to trust that an audio recording is authentic.

Famous calibration texts:

Stackexchange question

The North Wind and the Sun

These may be problematic if the target language includes sounds that do not occur in English, though interpolation or extrapolation may be sufficient.

[tgeaiqgh] 1958 Tybee Island B-47 crash

According to Wikipedia, it is unknown to this day whether the lost bomb (a Broken Arrow incident) had a plutonium capsule or the plutonium capsule had been removed and replaced with a lead one for training purposes.  This seems like a catastrophic failure of record keeping, separate from the catastrophic airplane accident: the government lost track of a large quantity (150 lb?) of plutonium.  If the plutonium capsule had been removed, where did it end up?

[vzirowdx] Rust game and free software

The Rust video game, in attempting social commentary by assigning players to an unchangeable race and gender, unintentionally clearly illustrated the issue that free software has been advocating all along: users should have control over their software.

The unhappiness that some players feel is not strictly because they are unhappy with the character to which they have been assigned, but because they do not get to exercise control over it.  They are locked in.

Tangentially, although the media would like to play the story up as male gamers feeling emasculated, I have heard anecdotes of heterosexual male gamers preferring a female avatar (in games in which one can choose one's character's appearance) for rational reasons, for example, if that's the character one is going to be looking at all the time, it might as well be pleasant to look at.

[fccsfygy] Spider playing a violin or guitar

Does a spider walking over the strings of a violin cause it to make enough noise as to be heard by a person in the same room?

Originally reported on a internet picture meme.

If it doesn't, then do it Mythbusters style: highly amplified electric guitar.

[brsrmbrz] Hydrogen times phi

To avoid harmonics, aliens (or humans) should broadcast (or listen) at the frequency of the hydrogen line times the golden ratio, not "hydrogen times pi" has mentioned in the movie Contact.  Phi is the most irrational number.  In contrast, pi is unusually close to harmonics at 22/7 and 355/113.  The frequencies of hydrogen times phi are, depending on whether one multiplies or divides, 2298.264784206 MHz and 877.8590324196 MHz, falling in the UHF band of microwave radio.

For frequencies more at human scale, divide by some high power of phi.  Phi^44 yields 1.1 seconds.

Or divide the Planck frequency by some high power of phi.  Planck time multiplied by phi^207 yields 0.98 seconds.

Or, broadcast gravitational waves.  It is vaguely possible that some natural process causes harmonic coupling between EM radiation and gravitational radiation.

[wuekezop] Hyperfine structure of ground state cesium

Neutral (i.e., non-ionized) cesium (caesium, cæsium) has 55 electrons, including a single electron in its outermost shell (valence shell).  Having a single outermost electron is characteristic of alkali metals, and hydrogen.

In the ground state, this outermost electron occupies the 6s orbital.  There is (exactly) one hyperfine transition possible for this 6s ground state electron: between spin up and spin down.  There is no hyperfine structure for the electrons in the inner shells because they are all paired (1 spin up pairing with 1 spin down) in completely filled shells.  Therefore, there is exactly one hyperfine transition for ground state cesium.  (The motivation for this post was, cesium atomic clocks are said to be regulated by the hyperfine transition of ground state cesium; however, which hyperfine transition?)

For ground state cesuim, the total electron angular momentum J has magnitude 1/2.  The total nuclear angular momentum I has magnitude 7/2.  The total atomic angular momentum F can take magnitudes F = 3 and F = 4.  Transitioning between these two F states (equivalently J = 1/2 and J = -1/2) induces the hyperfine structure.  F = 4 is the higher energy state.  The difference in the two energy levels corresponds to radiation with frequency exactly 9192631770 Hz, providing the definition of the second.

The speed of light is also an exact number by definition, so the wavelength (lambda = c/f) can be expressed as an exact rational number: 21413747/656616555 meters.  This might be the only wavelength that makes sense to be expressed as an exact rational number.  The frequency factors as 2 * 3 * 3 * 5 * 7 * 7 * 47 * 44351.  The speed of light (in m/s) factors as 2 * 7 * 73 * 293339.  The greatest common factor is 14.  Had humanity settled on different base units for time and length many years ago, these numbers would be different.

The wavelength happens to be a human-scale length: about 3 cm or 1.25 inches.

Incidentally, starting from the ground state with its electron in the 6s orbital, the most common excited state pushes the electron to the 6p orbital, yielding the high intensity spectral cesium D lines.  The 4f and 5d orbitals (and others) are harder to get to.  There are two possible excited 6p states, corresponding to J = 1/2 and J = 3/2 (yielding 2 D lines).  In the latter, F can be 2, 3, 4, or 5 so there are many hyperfine transitions between them.

References from which this post was written:

Cesium D Line Data, Daniel Steck

http://physics.nist.gov/PhysRefData/Handbook/Tables/cesiumtable3.htm

[soblhbbm] Computers playing go 囲碁 endgames

Monte Carlo go 囲碁 programs currently play "slack" moves if they are sure they are going to win, or lose, which is aesthetically not pleasing.  This could easily be fixed by adjusting komi when it starts doing that (which can be detected when the evaluation is near 0 or 1).  Evaluate the position for a range of komi.  This of course is computationally more expensive, maybe doable for analysis.

Just how strongly can Monte Carlo go 囲碁 programs play endgames?  As well as a human pro?  Better?  Can they handle combinatorial game theory as described in Mathematical Go?

[alazzrkk] Encoding data in Korean

One can convert a number to base 11172 then express it using the Precomposed Hangul syllables Unicode block (starting at code point 44032 decimal).

The large block itself is actually form of mixed radix notation, with the multipliers being, from big-endian to units, 19, 21, and 28.  This is useful for visually looking up the code point of a character.  There remains the problem that some jamo are visually very similar, so vulnerable to noise.

[hrpyultg] 21 cm toys

Create toys and trinkets featuring the length 21.10611405413 cm, the wavelength of the astronomical hydrogen line.  One of the most important lengths in the universe happens to be human-scale.  Usually things are much smaller or much larger.

Most interesting would be an antenna whose resonant frequency is 1420 MHz.

Incidentally, how can the value 21 cm be derived from quantum first principles?  It must have originally been done so to make the astronomical prediction, because the spontaneous transition is too rare to be observed in a laboratory, and hydrogen masers had not been invented yet.

[mpzjfeyb] Text contrasting margin

The color of text should be the opposite of the color of the margin area that is inaccessible to printing.  For most screens, that color is black, so text should be a light color.  Paper is white, so text should be black.

When using a glowing screen in a dark environment, the inaccessible area beyond the edge of the screen is of course black.

Text can go all the way to the edge of the printable area but still have contrast against the background of the margin.  Inspired by the failure of black text on a white background with text extended to the very edge of the screen.  The first letters of each line merged into the black margin, especially left side vertical strokes B b D E F H h I i K k l L M m N n P p R r U u.

[rvkxatlh] Role model

Under what conditions will a person, famously a child, emulate someone else's behavior and be convinced not to think critically about their emulation?

Of course, inspired by the politics around role models, including censorship of media depicting bad role models and punishment of public figures deemed bad role models.

The typical argument is that someone will assume causality from the bad behavior to high status.  But the causality is often kind of a stretch, so requires deliberately ignoring the instinct to think critically about the "stretch".  When do people not think critically?  What incentives cause not thinking critically?  Perhaps bad role models are dangerous only in environments which also have incentives to destroy critical thinking, for example, parents requiring of their children not to think but obey.  Placing the resulting blame for the emulation on the role model seems wrong in that case.

Create fiction subverting the trope: a character surrounded by seemingly terrible role models but chooses not to emulate them.  Or, surrounded by good role models but the character turns out bad.

[tkihzbvq] Managing incognito cookies

A more paranoid mode of incognito mode found in browsers:

Cookies are not shared between tabs or windows.

Open link in new tab does not transfer cookies to the new tab.  This might be a little confusing for users: a new tab may seem to log out of a site, but they will easily be able to learn and understand this simple model.

Also avoid setting HTTP Referer when opening a link in a new tab.

Websites that open new windows or tabs might break, but those are not really nice websites anyways.

Alternatively, have some UI way of depicting that one tab is a child of another tab, so share the same cookie jar.  Maybe each window has its own cookie jar.

Clicking on a link that exits the current website also creates an empty cookie jar for the new website, preventing cross site cookies.  Pressing "back" restores the old cookie jar.  Pressing "forward" restores the new cookie jar.

Also consider not setting HTTP Referer when following a link that exits the website.  So HTTP Referer would only be set for internal links and embedded content (e.g., images).

Perhaps the UI always opens a new window when exiting a website to make it more clear that it is a new cookie jar.  User configurable.

UI for user to manually specify transferring over cookies to another tab.

Also, things other than cookies that act like cookies, e.g., beacon images.

[xomqwiod] Freenet specification

Things not documented very well, yet, except as source code:

Disk file format of cache, store, etc.

Wire data format of peers communicating with each other, assuming knowledge of relevant cryptographic keys.

The lack of documentation is probably due to laziness (lack of resources), but possibly security by obscurity.  The above two might make life easier for attackers.

The Freenet Client Protocol is documented.

[krhenuna] Just a calculator

First, an evolution of mechanical devices for calculating:

Adding and subtracting in unary.
Adding and subtracting in decimal (abacus).
Multiplication and division.
Roots, powers.
Logarithm and exponential.
Trigonometric.
Special functions.
Matrices.
Abstract algebra.
Programmability.

At what point does a calculator have so many features -- too many features -- that it becomes something more than just a calculator?

Consider drawing the line at, the features that are built in to the calculator are limited to things that have mathematical purity, a timeless unchanging quality to them.  Near the border: the conversion rate between inches and centimeters is included, but the conversion rate between dollars and yen is not (requiring network to keep up with the changing world).  Similarly, time zone conversions are not included.  The speed of light is included (defined to be a constant value), but the fine structure constant is not: it can still change due to better scientific measurement.

Things that are not mathematically pure are required to be user input.

An algorithm to compute something (e.g., a graph algorithm) is included, even though in the future better algorithms to compute the same thing might be developed.  The algorithm as a mathematical function from input to output remains unchanged.

Probably make an exception for built-in "help" text documenting itself, even though documentation can be improved over time.

[jxgfbqmx] Daddy

Investigate the etymology of the word "daddy" meaning male object of affection, often erotic affection.

Incest is supposedly a taboo in all cultures.

[smgzmobb] Horror is not safe

Anything described as "safe", especially "feeling safe", can be turned on its head to be a template for horror fiction.

Inspired by the political controversy around "safe space": writing horror subverting it seems very easy.  Is there such a thing as politically incorrect horror?

[xomvdqgt] Words of random lengths

Given a corpus, construct a trie annotated with counts or probabilities.  Implicitly or explicitly include the probability of the end of a word.  What features does this trie have, in particular features of the probability distribution of children of a node?

Synthesize a similar trie for an artificial language, seeing to emulate the "shape" of words of a natural language, for example, the distribution of word lengths.

Original goal was to create a red herring: text that looks like natural language that has been coded by a substitution cipher, having structures resembling natural language, but which is actually randomness.  (Kind of the opposite of cryptography: cryptography is things that look random which aren't; this is things that don't look random but which are.)

Common roots and suffixes are probably too difficult for a trie; we would need a directed graph, with words generated as a Markov chain.  Maybe cheat and assume that all roots have been compressed down to one character in the artificial language.

Easiest might be a trie whose probability of the end-of-word symbol increases by depth.  The non-end-of-word children of a node have some skewed probability distribution.  Generate this trie on the fly while generating random text, expanding (and remembering) nodes only as needed.

[fufxfanw] Circular symbols

Create a writing system or data encoding system that can pack arbitrary amounts of data into a circular region (disc), of course, requiring finer resolution at high density.

Most obvious is concentric circular segments.  The radial width of the segments decreases as the density increases.  How many angular segments per circle should there be, for a given radius (radial distance / radial width)?

Inspired by go 囲碁 kifu with numbers from 1 through (usually) 200ish written inside circular pieces.  Three digit numbers are the wrong shape for a circular region.

Spherical barcodes (future post).  We could also consider packing data inside a sphere.

[uxdaxoii] Hexagon and hypercube

The length of the space diagonal of a 4-dimensional unit hypercube is 2, not an irrational number like for 2 and 3 dimensions.

The length of the longest diagonal of a regular hexagon with side length 1 is also 2.

This might be why the 24-cell honeycomb and the hexagon tessellation are considered related.

[dmuwqriz] Keep the protons together

Compute the strength of the electromagnetic repulsive force between protons in the atomic nucleus, probably strength per unit mass, and realize just how powerful the strong nuclear force is.  The strong nuclear force does not merely balance electromagnetic repulsion of protons: for small nuclei it's very hard to induce fission or radioactive decay by perturbing them with particle collisions.  (Larger nuclei are another matter, often easily willing to give up positive charges by alpha or positron emission.)  Similarly, it's amazing that small nuclei get more stable (so release energy) by stuffing more protons into a small region through fusion.

[fojwzpbc] Japanese numbers

Japanese numerals, Unicode code points in decimal, and some alternate forms.  They are scattered through the CJK block, in contrast to the digits 0-9, which are clustered in order.

0123456789
38646199682010819977222352011620845199712084320061
柒 or 漆
1229522769243362144232902202373852026578 or 284222542029590

10100100010000
21313303342131519975
陌 or 佰阡 or 仟
2534238476 or 2033638433 or 2019133836

The alternate forms that are commonly used are 0 (not an accounting character), 1, 2, 3, 10.  However, it also seems possible to alter the following characters by adding or erasing strokes: (5,9) (5,10) (5,1000) (5,10000) (6,8) (6,10000^4) (7,10) (7,10000^3) (8,10000^3) (9,10000)

10000^210000^310000^410000^510000^6
秭 or 𥝱
2074020806201402241931213 or 153457

10000^710000^810000^910000^1010000^1110000^12
313312831728567274913661726997

Even larger numbers are no longer single kanji.