Thursday, March 15, 2018

[uubpwgfn] Paradox of promiscuity

Having sex, aiming for enjoyable sex, is inherently a risky activity: you have to put yourself in a physically or emotionally vulnerable state to maximize enjoyment.  However, things could go wrong in such a state: you could get hurt.  To handle and recover from things going wrong requires a positive attitude, mental fortitude: high self-qi.

Therefore, one would expect a correlation between people who have sex with many partners and high self-qi.  Therefore, we would expect that people believed to have had sex with many partners would be prized for courtship: prefer partners who signal (as in game theory imperfect information) high self-qi.

This seems not to be occurring: In women, promiscuity is very frequently looked down upon ("slut"), and in men, although it carries value ("stud"), the meaning of that value does not seem to be because it directly signals high self-qi.

Possible explanations resolving this paradox:

This model of self-qi is entirely wrong.

The reason some people have had many sexual partners is because they can't retain them, losing them because of their own low self-qi or some other flaw like lack of commitment or loyalty.

Self-qi is a currency that can be used to advance yourself in many ways.  Those who choose to spend it on having sex are doing so because of lack of other opportunities, signaling low social status.  Future post: on the history social dancing.

People are not being rational in how much sex they have.  This seems incorrect: people make less mistakes the more chances they have to try and learn from their mistakes, so a promiscuous person for whom promiscuity is rationally bad decision will learn not to have sex so often.  Similarly, those for whom promiscuity is rationally a good decision will shift towards it, though this is contingent on other people wanting to have sex with you.

[obxqhvtm] Contagious handrails

Should you hold the handrails of public stairs or an escalator?  On one hand (no pun intended), you are touching the thing everyone before you touched, so exposing yourself to everything contagious those people had.  On the other hand, stairs are some of the most vicious killers out there due to slips and falls.  Even a light maiming by stairs can leave you injured for life.

The problem is somewhat game theoretic. The degree to which handrails are coated with contagious disease depends on how much everyone else touches it.  The degree to which everyone else touches it depends on what they believe to be the contagiousness of the handrail.

[ekeyyuib] Many vulnerable android devices?

How many active Android devices are out there, no longer being patched for security vulnerabilities by their manufacturers?  It is of course a shame that otherwise perfectly fine hardware reaches this state: DRM at work, as well as not-too-large an ecosystem of alternative well-maintained distros one can install on one's phone.

Wednesday, March 14, 2018

[kfernrxl] Politics and pro wrestling

Tell a story juxtaposing the behind-the-scenes of both politics and pro wrestling, each side scripting a story for the people to consume, full of invented and hyped-up conflicts.

Sunday, March 04, 2018

[omvgtkqp] Dodecahedral edge cover

Can one partition the faces of an icosahedron into 10 non-overlapping pairs of adjacent faces?  Some simple investigation suggests yes.  If so, one can set up a grid on each nonplanar rhombus by connecting opposite edges.  If distortion is OK (e.g., in a game), this can be a map with 10 square shaped regions connected to each other.

Are there any nicely symmetric face pairings?  Zonohedra, polyhedra with all faces parallelograms (the "more restrictive definition" according to George Hart) exist, including the nicely symmetric rhombic dodecahedron and rhombic triacontahedron.

Equivalently, this partitions the surface of a sphere into 10 congruent rhombus shaped patches.  Equivalently, it is an edge cover of the regular dodecahedral graph.

What happens when this is done on a octahedron?  There seem to be two ways of doing it: 4 wedges from pole to pole, or 2 sideways with respect to the other 2 reminiscent of a sphericon.

[hurozhls] Large chess is like go

Chess on large boards and especially in higher dimensions might feel more like go 囲碁.  There are many battles going on in different parts of the board which only weakly interact because it takes many moves for a piece involved in one battle to move to influence another battle.  Perhaps enhance this characteristic by limiting long-range movement to only the movement of the small rook, parallel to orthogonal axes.  Another possible enhancement: forbid long-range captures.

Change the scoring to be more like go.  There is no king, no checkmate.  The game ends with 3 fold repetition or consecutive passes.

For a static final position (consecutive passes) score it by something like territory: maybe the number of squares your pieces can reach before any opponent's piece.  If the final position is a loop (repetition) take the average over the loop.  Scoring is complicated and best done by computer.

Perhaps the initial position has every square occupied, so there is something to play for, not immediately passing.

[bljdmymf] Shortest paths for higher dimensional chess pieces

Given a higher dimensional rook or bishop as previously described, compute a path which reaches a given destination in the smallest number of moves.

In 2D on an empty board, a rook or bishop takes at most 2 moves to reach any given (accessible) square, and it is not difficult to describe the positions in which they require only 1.

In N dimensions, I suspect at most N moves are necessary (which is a lot).  When can we get there in less, and how?

The movement of both pieces can be described as a integer scalar multiple of a vector whose components are all -1, 0, or 1.  For a bishop, the number of nonzero components is even; for a rook, odd.  Without loss of generality, assume the piece is at the origin.  Find moves which sum to the coordinates of the destination.  This seems reminiscent of bin-packing.

One heuristic is, for all possible moves from the current location, choose the one that minimizes the straight-line (Euclidean) distance to the destination: the distance from a point to a line.  Repeat for the next move.

Other open problems: computational complexity; the tricky knight; what if there are obstacles?

[tjwlghtv] Limited higher dimensional chess pieces

A family of additional pieces for higher dimensional chess:

The Small rook, wazir, and dabbaba move only parallel to orthogonal axes.  2*D possible directions.  This is the most obvious generalization of the rook to higher dimensions, but originally rejected because of how relatively weak it becomes in higher dimensions.

The Small bishop, ferz, and alfil move only in the directions of longest-length space diagonal.  In odd dimensions, the pieces are not colorbound.  2^D possible directions.

The Small knight jumps to a square reachable by one Small wazir move then one Small ferz move in the outward direction.

Of course, these abilities can be combined to form compounds like a queen.

Compared to the Great versions of the pieces previously described, these pieces are relatively much weaker.  The Great rook and bishop both move in approximately 3^D/2 possible directions.  However, the weakness of the Small versions might enhance a game in which pieces rarely interact over large distances.

Saturday, March 03, 2018

[eltiajwk] Short Diceware

We consider generating passwords using dice, inspired by Diceware.  However, unlike Diceware, we generate short, non-memorable passwords, intended for use with a password manager.

A-Z a-z 0-9 and two punctuation give 64 characters, suitable for 2 throws of a d8 (octahedron) die, looking up the letter in a compact table, in contrast to Diceware's very long lists.  The choice of the 2 punctuation characters depends on what punctuation is permitted for that site.

A d20 labeled with the 20 most common initial letters.  d24 and d30 exist as Catalan solids.  For d30, the 4 extra faces could be reroll, common letters (maybe vowels?), numbers, or punctuation.  Previously, on how to turn a random string into a sentence.

[tvuxbiuq] Password generation with a deck of cards

Easiest is to mark up the fronts of deck of 52 cards with lowercase a-z and uppercase A-Z.  (It's convenient how the numbers work out.)  Shuffle and get some random letters.  Drawing with replacement (shuffling after each draw) has slightly more entropy, but requires more effort.  Use the number cards (rejecting face cards) if you need to add some digits to satisfy password character class requirements.

We need a way of writing individual letters to distinguish uppercase from lowercase: c o p s u v w x z.  Maybe tilde or macron for lowercase, as these conveniently do not have ascenders.  Or cursive.

Slightly more sophisticated is to add 10 number cards from a separate deck, bringing the total up to 62: letters and digits. Add jokers or more face cards for punctuation.

Sites often disagree on what punctuation is permitted/required.  Is there a set of 2 (for jokers) or 3 (for face cards) which are usually permitted?

These would not be memorable passwords, so use a password manager.

[ebxhxgtj] Despacito magnets

The song Despacito could be interpreted as about science, the attraction of metal to a magnet.  Create a music video to the song illustrating magnets in action.

[ttjsbzma] Avoiding the birthday paradox

Each person draws with replacement from an urn containing N balls.  For a given population size, how large should N be so that the probability of collision is smaller than some given small probability?  Of course, larger than Population^2 because probabilities are around 50% there.

If we want collisions to "never" happen, what should that small probability be?  2^-128? 2^-256?  Randomly chosen 128-bit UUIDs only offer 2^64 collision resistance, probably OK for each human on earth choosing just one, but not enough for (say) tagging rapid transactions.

Inspiration was, how does a galactic civilization with a population on the order of 2^114 choose unique identifiers, e.g., the future equivalent of Social Security Numbers, for each person in a distributed way (not requiring central coordination because communication might be expensive)?  Or, how should it assign IP addresses to its galactic network of computers (though that might be more difficult, also requiring solving routing)?

[iaqaplhi] Star Trek: K3

Tell stories of a Star Trek-like universe (people generally get along, not war all the time) taking place in a galaxy colonized to Kardashev level 3.  Most stars have Dyson spheres (swarms) around them.  We probably need FTL travel and communication.

Assuming a person requires an average of 4 kW of power (including energy cost of agriculture to grow their food), a galaxy's power output can support a population of 10^34.

If this were instead a Star Wars-like universe with such a population, a quadrillion deaths would not be a big deal, proportionally less (much much less) than 1 person dying on our planet of 7 billion.

[dpxfesvt] Inventing evolving languages

Invent not just one fictional language but multiple versions of it corresponding to snapshots over time for a story that takes place over a very long time.  How do languages realistically evolve?  Inspired by Tolkein.

[iiycledq] Fastest cryptographic RNG

How quickly can cryptographically secure pseudorandom numbers be generated?  Probably something parallel that runs on GPU.

Assume that we are consuming such a large quantity of random numbers that statistical irregularities that show up after 2^64 samples will become visible.  This means we cannot just use AES in counter mode to generate a random stream.

This seems useful only as a curiosity: what could need so much cryptographic randomness so quickly?  Monte Carlo simulations do not require cryptographic security.  What could even consume numbers that quickly?

Maybe high-bandwidth encrypted communications of data at rest.  Other than data at rest, it's hard to imagine data being produced so quickly as to require an extremely fast cPRNG to encrypt it.  But even data at rest is limited by disk bandwidth.

[rgifeuwg] Human power

Another way of putting amounts of power or energy into human-comprehensible terms is to compare it with a human on an exercise bike.  Previously.

[dlowwfka] Car average power

A car with fuel efficiency of 20 miles per gallon traveling 20 miles per hour on average conveniently consumes 1 gallon of gasoline per hour (similarly 30 and 30, etc.).  This translates to 36000 watts.  Less if your car has better gas mileage.

[qdkedsco] Thwarting the evil maid

Preventing physical attacks against unattended computers carrying valuable data is simply the problem of physical security, e.g., safes and locks, which has been studied for a very long time, though this is a new form factor.

Desired features: A laptop which can be locked closed with a lock (maybe padlock) of the user's choosing so that the user can balance security versus convenience.  Laptop cannot be disassembled while locked.  Ports cannot be accessed while locked.

Some users may want tamper-proof physical security; others may just want tamper-evident physical security.  Tamper-evident can interface with the computer to record and notify attempts at tampering.

[smofltff] Connect the dots

In a workbook, provide many pages offer practicing drawing the same image many times with numbered dot-to-dot.  Later pages for the same image have fewer and fewer dots.  This teaches how to draw.

The last dot or number before a discontinuity is marked with some symbol indicating pick up your pen and restart at the next number.  A picture does not have to be a single continuous line.

[fqdnhwqh] Even versus odd dimensions

Enumerate geometric things which behave differently depending on whether the number of dimensions is odd or even.  Inspired by algorithms in computational geometry.

[dccpeblm] CNN CA

Convolutional neural networks and cellular automata like Conway's Game of Life seem like a good fit, but not sure exactly how.  Maybe spaceship searches and design, searches for other interesting objects, or design of universal circuits and constructors.

Sunday, February 25, 2018

[xucvjwda] Pari/GP first-stage ECM time

Number of seconds pari/gp's factorint function spends on other algorithms before trying MPQS for factoring numbers of various sizes (in bits).  Most of that time is spent on the Elliptic Curve Method.  Hardware and software info:

Intel(R) Core(TM)2 Duo CPU E8600 @ 3.33GHz
GP/PARI CALCULATOR Version 2.9.4 (released)
amd64 running linux (x86-64 kernel) 64-bit version
compiled: Jan 16 2018, gcc version 5.4.0 (Funtoo 5.4.0)
threading engine: single

for(n=95,151,p=precprime(2^n);q=precprime(p-1);T=gettime();factorint(p*q,9);print(2*n," ",(gettime()-T)/1e3))


One additional data point from a different computer and different software version: 299 bits (10^90-81), 5767.238 s.

Friday, February 23, 2018

[gmiuenaz] Base 30

Yet another partial attempt (previous attempts yet to be published) at creating something like MIME quoted-printable, a way of encoding any Unicode code point using only printing 7-bit ASCII characters while still keeping English text vaguely readable (so not say Base64 applied to UTF-8).  If there's anything I've learned, there are many ways to do this.

We want the letters a-z to keep plain text readable; let's choose lowercase.  We want space, though maybe we want to use underbar or period as space (similar to URL encoding using plus as space).  We want an escape character, say semicolon (;).  We choose it because it is on the home row on QWERTY keyboards.  Add parentheses because matched delimiters are useful if we want to encode hierarchical structure.  This yields 30 characters.  We could do more, but for simplicity start here.  Previously similar.

Similar ideas: if the escape character were backslash (\), text would look like C strings or LaTeX.  If the escape character were ampersand (&), text would look like HTML.

Characters that are not the lowercase letters or space are encoded in two possible ways:

  1. Long Parenthesized escape sequences ;(something)
  2. Short escape sequences ;lowercase

Let's choose uppercase to have short escape sequences, specifically the escape character followed by the letter repeated: ;aa ;bb...  Numerals should be similar, though there's a choice between (a=0 ... j=9) or (z=0, a=1 ... i=9).  The former sorts better; the latter follows models like Greek and Hebrew which have used letters as digits though perhaps not in place-value systems.  (Or we could just add 0-9 to the 30 letters.)  Let's choose 0=;z ;a ;b... ;i=9.  Numerals get the second shortest escape sequences.

Short escape sequences in general start with semicolon followed by a sequence of lowercase letters.  How should a short escape sequence end?  Several possibilities we could choose: a space, the escape character again, or the sequence of lowercase letters encodes its endpoint.  The latter is what UTF-8 (very roughly) does: the high bit in each byte indicates we're still in an escape sequence.  More generally, the escape sequence could traverse a Huffman-tree-like structure where in we know we've hit a leaf because we know the structure of the tree.

Variations possible: if we had more than 1 escape character, then different escape characters could be the root of different trees.  UTF-8 could be interpreted as having 128 escape characters.

Let's choose short escape sequences to end with either a space or the escape character again, but the latter signifying the start of another escape sequence.  This keeps compact things like digit sequences.  It does introduce a few awkwardnesses: the encoding of a character requiring an escape sequence followed by a character not requiring one will awkwardly have a space in it: camelCase = camel;cc ase.  A character requiring an escape followed by a space awkwardly needs to be encoded with two spaces after it: the capital letter ;aa  has decimal ;aa;ss;cc;ii;ii  value ;f;e .

Short escape sequences are reminiscent of HTML entity references, though the latter use characters beyond a-z, like uppercase.  They also explicitly mark the end of a reference with a special character, semicolon.

There is no difficulty in finding the end of a Long Parenthesized escape sequence so long as we enforce that parentheses match.

The escape sequence of semicolon immediately followed by a space is uniquely the shortest escape sequence.  Let's keep it unassigned; maybe it gets used by the UI to signify something special like leaving typing mode (similar to vi), or the user can assign it.

At this point, all that remains is to assign escape sequences to the all the rest of the Unicode code points.  Long escape sequences permit many schemata, each preceded by a schema identifier.  One possible schema is a formula to convert back and forth between a Unicode code point number and a digit sequence in base 26.  It's not strictly a number is base 26 because leading "zeroes" (the letter a?) matter.  Use the formula for the sum of a finite number of terms of a geometric series.  Unfortunately, some will spell out vulgar words.

Long parenthesized escape sequences also intriguingly permit a rich Lisp-like language with different combinators for expressing the how a complex Unicode character is put together from components.  This requires the structure of complex Unicode characters be broken down into their component parts.  This probably already exists.  Previously, thoughts on Japanese and investigation into Korean (Hangul).

[hclhaknu] Seven Usual Suspects

Mashup The Usual Suspects and Se7en, both movies with Kevin Spacey playing a clever villain, so they take place in the same universe.

Thursday, February 22, 2018

[mkhbjbvh] Chess on a hypercube

Adapt chess on the surface of a 6x6x6 cube to the hypersurface (a 3D manifold) of a 6x6x6x6 4D hypercube (tesseract).  Apply this movement of 3D chess pieces.

A tesseract has 8 cubical cells that comprise its hypersurface.  There are the top and bottom cubes (promotion areas), and 6 side cubes which are connected roughly as the 6 faces of a cube are, as seen in the famous cube-within-a-cube cell-first perspective projection of the tesseract.

There are some literal edge cases of bishops hitting edges that need to be thought through (probably movement through an edge prohibited), similar to bishops hitting corners when playing on the surface of a cube.  3D knight moves through edges and rooks through corners also require thought.

Each player starts with 216 pawns, 54 rooks, 54 bishops, 54 knights, 27 queens, 26 commoners, and 1 king: total 432.  Board area 1728.

Sunday, February 18, 2018

[oebfsidv] Taxicab numbers

There are many ways to generalize the Hardy-Ramanujan number 1729:

The {a}th number which can be written in at least {b} different ways as the sum of {c} numbers all of the form {d}^{e}.

The {d}s could be restricted to positive and/or relatively prime.  The form {d}^{e} could be relaxed to any form, e.g., triangular numbers (Gauss's Eureka theorem).

The most famous generalization is the sequence that is a function of b, restricting a=1 c=2 e=3 and d=non-negative.

I like the sequence that is a function of a, b=2 c=2 e=3 and d=unrestricted.  This is A051347.  Allowing negative numbers seems appropriate for the cubing operation as the range of cubing extends to negative numbers (unlike for squaring).  If cubing can do it, let it.

Waring's problem is about b=1, and its most narrow form restricts to nonnegative d.   But how many signed cubes (what value of c) does it take to express any sufficiently large number?  Probably 4 (same as with positive-only, though the "sufficiently large" threshold might be different).  Coincidentally, this is the same number of squares needed, by Lagrange's Four-Square Theorem.

Incidentally, it is not too difficult to notice that 1729 can be expressed as the sum of positive cubes in 2 different ways.  If one happens to have cubes memorized up to 12^3=1728, then one has probably also noticed that 9^3=729 differs from 12^3 by almost exactly 1000, and 1000 is also a cube.  From this, it is easy to realize 12^3+1^3 = 9^3+10^3.

[pkobcsan] Polyhedron facts

Cube: 6 faces, 8 vertices, 12 edges, 24 face-vertex tuples, 24 face-edge tuples, 24 edge-vertex tuples.  98 items total, maybe good for a deck of cards for a game.

Same for octahedron.

Tetrahedron: 4 4 6, 12 12 12 = 50 items.

Dodecahedron / icosahedron: 12 20 30 60 60 60 = 242 items.

Vaguely an extension of half-edge data structures for computer graphics.

For a general polyhedron, the cards could include additional information in the style of Pokemon cards.  Faces, edges, vertices get names.  Face: fraction of total surface area, number of sides, number of holes, fraction of the interior volume closer to this face than to any other face.  Edge: length (in what units?), dihedral angle, adjacent faces, adjacent vertices, fraction of close interior volume.  Vertex: degree, spherical angle of interior, fraction of close interior volume.  Face-Edge: which vertex is to the left and which is to the right when standing on the edge facing into the face, fraction of the area of the face closer to this edge than any other edge, fraction of the perimeter of the face.  Face-Vertex: angle, which edges are to the left and to the right when standing on the vertex facing into the face, fraction of the area of the face closer to this vertex than any other vertex.  Edge-Vertex: which face is to the left and to the right when traveling along that edge to the vertex.

Edge length could be scaled relative to the longest edge, total length of all edges, maximum distance between two vertices (diameter).

In general, a card contains a fixed amount of information, so we do not for example list all the edges of a face because that is unbounded in number.

We could also define the "angle" of edge on a polygonal face by imagining the face at the center of a very large coplanar circle, and computing what part of that circle is closer to some point on that edge than to any other edge on the face.  For nonconvex polygons, this angle could be zero.  This probably already has a name.  It seems related to Voronoi.  Similarly, spherical angle of a face or vertex.  Maybe also angle of an edge visible from an infinite sphere.

Or, again consider the plane of a face.  Bisect the angles of the vertices adjacent to an edge of a face: give the angle between the two lines, negative if they intersect on the exterior of the polygon due to concavity.  Call this local convexity.

We could also concretely define a center of a face or polyhedron as the centroid and give angles, areas, volumes, distances.  These values might be negative for faces with holes, concave shapes.

Previously, on adding edge cards to a deck representing the vertices of the Hoffman-Singleton graph.

In 4D each face touches 2 cells.  Edges bound an arbitrary number of faces so we would no longer list all of them.  We probably need to consider 3-tuples instead of (in addition to?) 2.  Use ideas from abstract polytopes to organize things.

[rtprjaew] Could we blow up to earth?

If we took all the deuterium and lithium on the earth's surface and crust and did fusion with it, would the energy released sum to more than the gravitational binding energy of the earth?  If not, how thick of a shell could be lifted to infinity? What smaller astronomical bodies could we blow up entirely?  Or, if the energy is more than enough to blow up earth, what larger bodies could we blow up instead?  Blowing up a gas giant avoids the need to bore a hole to the center.

(Why blow up a gas giant?  Because it's there of course.  Though the astroengineers can probably think of a better reason.  Maybe to get a clear shot at a moon on the far side with a rebel base.)

What if we used all the lithium and deuterium on and in the planet, not just the crust?  Though the process of extracting it might leave the planet pretty destroyed.  Which element is the limiting reagent?  If it is deuterium, can we effectively make more deuterium by fusing a neutron to protium?  What other elements can be straightforwardly fused to release energy (i.e., not iron) in a multi-stage thermonuclear bomb?

The original thought was, there is no known upper limit on how large and powerful we can make a thermonuclear bomb, especially one utilizing 3 or more stages.  Making one large one instead of many small ones is more efficient because the former only requires one primary fission bomb.  Of course fission could supplement fusion, but I suspect the total energy available on earth from fission is much less than from fusion.

Depict in science fiction scientifically accurate very large thermonuclear bombs, perhaps planet busters.

[ewzsytrb] Artist caste

The people who make entertainment are often a very different group in society than those who consume entertainment, the latter usually more wealthy.  How do the creators know what to create, what will appeal to people whom they are very culturally different from?

Inspiration was African-Americans who performed jazz and blues, whose recordings were probably mostly purchased by whites.  Presumably the record producers bridged the gap, communicating to the composers and musicians what they believed would sell well.  Exactly how and what did they communicate?

[fbdvgmvu] More computer Jeopardy

There interestingly haven't been follow-ups to Watson playing Jeopardy: computers competing in knowledge competitions.  Lots of room to explore things like tricky questions that might give humans an edge, or different computers playing against each other.

[bpkyrail] Text with timestamped keystrokes

Create an editor which records a time and date for each character, when it was typed.

It could also record the times when characters were deleted, for saving undo state.  Deleted text might be visible grayed out or with strikethrough.

[ypndkvis] Not left-handed chess

When playing strictly by the rules, you are supposed to push your chess clock with the same hand that you move your pieces.

After initially using his or her left hand, a player dramatically declares, "I am not left-handed", and so on, mimicking The Princess Bride.

The duel references chess in naming attacks and defenses.

[irufelsj] Monospace text when mouse UI

Whenever the user might be using a mouse (or finger for touchscreen) to interact with text, e.g., selecting text or positioning a cursor for editing, the text should be in monospace font, because precisely positioning a mouse cursor among long thin characters like lowercase L in proportional font is difficult by Fitts Law.

Ironically, it is old-school terminal applications which use monospace, despite them mostly not using the mouse, perhaps running in environments (e.g. console) which don't take mouse input.  These would be fine in proportional font.

Saturday, February 17, 2018

[jxbgqbof] Boring football

Every possession begins on the 50.  Scoring is by total yardage.  A touchdown simply completes a 50-point score and ends possession.  Getting tackled behind the line of scrimmage loses points.

No field goals, no punts, no kickoffs: essentially we've just eliminated kicking, anything having to do with a foot contacting a ball in football.  On fourth down you always go for it.

Turnovers end possession, and then the opposing team begins on the 50.  If there was yardage loss on the turnover, then the loss is subtracted, similar to a play ending behind the line of scrimmage.  A safety is a turnover (which must have been preceded by a 50 yard loss that possession).  Turnovers can be costly: lose up to 50 points on your possession then immediately give your opponent the opportunity to gain 50 more.

Like in regular football, the following can all be easily adjusted: field length (currently 100 yards), number of downs (currently 4), first-down distance (currently 10 yards).

A 20-yard field might be interesting: all red-zone, all the time.  Every possession begins 1st and goal at the 10, and every possession lasts at most 4 downs.  One cannot earn additional 1st downs.  Even more extreme: 2-yard field.

[zpqnupzy] Slow feedback on durability

People create many things designed to last a long time.  Some actually do.  After the long time and some things have survived and some not, are there surviving records of how the things were made, recorded with enough precision to be able to determine what construction techniques caused which things to survive longer?

Inspired by very old mosaics as a possibility for long-term preservation of data.  How was the cement made?

[wjfejort] A decade of independence referenda

An independence referendum, voting for a portion of a country to secede, should be repeated.  Only after 10 years of consecutive yesses should it count: this is roughly the length of a business cycle of recession and boom, so thwarts a populist from taking advantage of a temporary change in the economy to induce a permanent change in a country border.

Should all decisions be made this way?

Inspired by Catalonia's independence referendum.

[qwpvxadu] PGP hanko

Create a stamp of the QR code of the fingerprint of your PGP public key for ease of communicating it to others in paper settings.  We need to specify a QR code format for key fingerprints.  Key fingerprints are normally expressed in hexadecimal, but hexadecimal is terrible for QR codes.  Decimal or raw binary is better.  Include the key identifier (e.g., email address in all caps) in the QR code.

Some experimentation yielded QR codes typically between 21x21 to 49x49 pixels depending on error correction level and what other information is included in the code.  What is the practical resolution of stamp?  This is probably going to be a fairly large square stamp.  Maybe better would a barcode that has a rectangular shape, which would work better in forms originally designed for text.

This is a good application for 3D printing (or milling) because everyone gets a uniquely different physical object; it cannot be mass produced.

Unlike Japanese hanko, this stamp isn't meant to be used as a signature (these would be very easy for someone else to copy by virtue of the error correcting code in QR codes).  They definitely do not cryptographically sign the document they are stamped on, despite cryptographic signatures being a popular use for public key cryptography.  That would require a different stamp for every document.

Alternatively, carry around a pad or roll of stickers each with your QR code on them.  This is a little bit weaker because a sticker could be removed and replaced with that of a man-in-the-middle.

[lfrgtxqf] Uniquely shaped maze rooms

Create a maze of rooms connected by passageways in which each room has a unique shape.  Useful for remembering whether you've been in a place, at least for people whose memory works that way.

VR or Minecraft.

[cxbuefac] Force Heat

Remake the diner scene between DeNiro and Pacino in Heat with the Emperor and Yoda. (Previously, on why they don't fight.)

[wihcptju] 2D manifold maze embedded in Euclidean 3D

The maze is 2D (every junction is straight, left, right, or backward) but the paths twist, curve, and fly around in 3D.  Assume the character is wearing magnetic boots.  Can the player keep track of where they are in 3D, forming a mental map in 3D?  Perhaps the task is to get to or near a point specified in 3D.  Easier might be if the path direction changes are also only orthogonal, walking up a wall or down a cliff.

Vaguely similar to Perplexus marble dexterity puzzle.

[uoujnmzg] Wanted masse

Adapt the movie Wanted with the characters curving billiard balls instead of bullets.

[omqzhxkn] Lagrange Four-Square Theorem examples

A listing of numbers and how to express them as a sum of 4 squares will probably provoke curiosity: There isn't an obvious pattern of how to express a given number as sum of 4 squares.  Can all natural numbers be expressed this way?  (Yes, by Lagrange.)  Which numbers can be expressed as the sum of just 3 squares (answer: Legendre Three-Square Theorem), or 2?  As numbers get larger, there seems to be a trend of more ways to express it as 4 or fewer squares, kind of reminiscent of Goldbach conjecture.  What is the rate of growth of the number of ways?  What about cubes and higher powers (Waring's problem)?  There's lots of deep mathematics lurking just beneath the surface.  It's just a short skip and a jump to Fermat's Last Theorem.

We generated 4-square decompositions up to 121=11^2 in order to include 112 = 7 * 4^2, the first instance where Legendre's 3-square theorem applies with an exponent (on 4) greater than 1.  The number which had the most number of ways to express it in the range was 90, with 9.

We also provide a more compact list which expresses each number in the fewest number of squares, but still listing all possibilities for that fewest number of squares.  The full version has 436 lines; the compact version has 188.  The compact version makes it more clear (perhaps inspiring more curiosity) which numbers require 4 squares and which ones can be done in less.

Similar lists could be made for Gauss's Eureka Theorem on sum of 3 triangular numbers and the Goldbach conjecture on the sum of 2 primes.

Haskell source code is here.  Here is a pedagogical excerpt of how to choose num decreasing numbers bounded by 0 and amax.  We use the list as a nondeterminism monad.

choose_n_of_max :: Integer -> Int -> [[Integer]];
choose_n_of_max amax num = case compare num 0 of {
LT -> error "negative choose_n_of_max";
EQ -> return [];
GT -> do {
  x <- [0..amax];
  y <- choose_n_of_max x (pred num);
  return (x:y);

Below is a machine-readable listing of the numbers through 121 and all the ways to express each number as the sum of 4 or fewer squares.

(0,[[0,0,0,0]]) (1,[[1,0,0,0]]) (2,[[1,1,0,0]]) (3,[[1,1,1,0]]) (4,[[1,1,1,1],[2,0,0,0]]) (5,[[2,1,0,0]]) (6,[[2,1,1,0]]) (7,[[2,1,1,1]]) (8,[[2,2,0,0]]) (9,[[2,2,1,0],[3,0,0,0]]) (10,[[2,2,1,1],[3,1,0,0]]) (11,[[3,1,1,0]]) (12,[[2,2,2,0],[3,1,1,1]]) (13,[[2,2,2,1],[3,2,0,0]]) (14,[[3,2,1,0]]) (15,[[3,2,1,1]]) (16,[[2,2,2,2],[4,0,0,0]]) (17,[[3,2,2,0],[4,1,0,0]]) (18,[[3,2,2,1],[3,3,0,0],[4,1,1,0]]) (19,[[3,3,1,0],[4,1,1,1]]) (20,[[3,3,1,1],[4,2,0,0]]) (21,[[3,2,2,2],[4,2,1,0]]) (22,[[3,3,2,0],[4,2,1,1]]) (23,[[3,3,2,1]]) (24,[[4,2,2,0]]) (25,[[4,2,2,1],[4,3,0,0],[5,0,0,0]]) (26,[[3,3,2,2],[4,3,1,0],[5,1,0,0]]) (27,[[3,3,3,0],[4,3,1,1],[5,1,1,0]]) (28,[[3,3,3,1],[4,2,2,2],[5,1,1,1]]) (29,[[4,3,2,0],[5,2,0,0]]) (30,[[4,3,2,1],[5,2,1,0]]) (31,[[3,3,3,2],[5,2,1,1]]) (32,[[4,4,0,0]]) (33,[[4,3,2,2],[4,4,1,0],[5,2,2,0]]) (34,[[4,3,3,0],[4,4,1,1],[5,2,2,1],[5,3,0,0]]) (35,[[4,3,3,1],[5,3,1,0]]) (36,[[3,3,3,3],[4,4,2,0],[5,3,1,1],[6,0,0,0]]) (37,[[4,4,2,1],[5,2,2,2],[6,1,0,0]]) (38,[[4,3,3,2],[5,3,2,0],[6,1,1,0]]) (39,[[5,3,2,1],[6,1,1,1]]) (40,[[4,4,2,2],[6,2,0,0]]) (41,[[4,4,3,0],[5,4,0,0],[6,2,1,0]]) (42,[[4,4,3,1],[5,3,2,2],[5,4,1,0],[6,2,1,1]]) (43,[[4,3,3,3],[5,3,3,0],[5,4,1,1]]) (44,[[5,3,3,1],[6,2,2,0]]) (45,[[4,4,3,2],[5,4,2,0],[6,2,2,1],[6,3,0,0]]) (46,[[5,4,2,1],[6,3,1,0]]) (47,[[5,3,3,2],[6,3,1,1]]) (48,[[4,4,4,0],[6,2,2,2]]) (49,[[4,4,4,1],[5,4,2,2],[6,3,2,0],[7,0,0,0]]) (50,[[4,4,3,3],[5,4,3,0],[5,5,0,0],[6,3,2,1],[7,1,0,0]]) (51,[[5,4,3,1],[5,5,1,0],[7,1,1,0]]) (52,[[4,4,4,2],[5,3,3,3],[5,5,1,1],[6,4,0,0],[7,1,1,1]]) (53,[[6,3,2,2],[6,4,1,0],[7,2,0,0]]) (54,[[5,4,3,2],[5,5,2,0],[6,3,3,0],[6,4,1,1],[7,2,1,0]]) (55,[[5,5,2,1],[6,3,3,1],[7,2,1,1]]) (56,[[6,4,2,0]]) (57,[[4,4,4,3],[5,4,4,0],[6,4,2,1],[7,2,2,0]]) (58,[[5,4,4,1],[5,5,2,2],[6,3,3,2],[7,2,2,1],[7,3,0,0]]) (59,[[5,4,3,3],[5,5,3,0],[7,3,1,0]]) (60,[[5,5,3,1],[6,4,2,2],[7,3,1,1]]) (61,[[5,4,4,2],[6,4,3,0],[6,5,0,0],[7,2,2,2]]) (62,[[6,4,3,1],[6,5,1,0],[7,3,2,0]]) (63,[[5,5,3,2],[6,3,3,3],[6,5,1,1],[7,3,2,1]]) (64,[[4,4,4,4],[8,0,0,0]]) (65,[[6,4,3,2],[6,5,2,0],[7,4,0,0],[8,1,0,0]]) (66,[[5,4,4,3],[5,5,4,0],[6,5,2,1],[7,3,2,2],[7,4,1,0],[8,1,1,0]]) (67,[[5,5,4,1],[7,3,3,0],[7,4,1,1],[8,1,1,1]]) (68,[[5,5,3,3],[6,4,4,0],[7,3,3,1],[8,2,0,0]]) (69,[[6,4,4,1],[6,5,2,2],[7,4,2,0],[8,2,1,0]]) (70,[[5,5,4,2],[6,4,3,3],[6,5,3,0],[7,4,2,1],[8,2,1,1]]) (71,[[6,5,3,1],[7,3,3,2]]) (72,[[6,4,4,2],[6,6,0,0],[8,2,2,0]]) (73,[[5,4,4,4],[6,6,1,0],[7,4,2,2],[8,2,2,1],[8,3,0,0]]) (74,[[6,5,3,2],[6,6,1,1],[7,4,3,0],[7,5,0,0],[8,3,1,0]]) (75,[[5,5,4,3],[5,5,5,0],[7,4,3,1],[7,5,1,0],[8,3,1,1]]) (76,[[5,5,5,1],[6,6,2,0],[7,3,3,3],[7,5,1,1],[8,2,2,2]]) (77,[[6,4,4,3],[6,5,4,0],[6,6,2,1],[8,3,2,0]]) (78,[[6,5,4,1],[7,4,3,2],[7,5,2,0],[8,3,2,1]]) (79,[[5,5,5,2],[6,5,3,3],[7,5,2,1]]) (80,[[6,6,2,2],[8,4,0,0]]) (81,[[6,5,4,2],[6,6,3,0],[7,4,4,0],[8,3,2,2],[8,4,1,0],[9,0,0,0]]) (82,[[5,5,4,4],[6,6,3,1],[7,4,4,1],[7,5,2,2],[8,3,3,0],[8,4,1,1],[9,1,0,0]]) (83,[[7,4,3,3],[7,5,3,0],[8,3,3,1],[9,1,1,0]]) (84,[[5,5,5,3],[6,4,4,4],[7,5,3,1],[8,4,2,0],[9,1,1,1]]) (85,[[6,6,3,2],[7,4,4,2],[7,6,0,0],[8,4,2,1],[9,2,0,0]]) (86,[[6,5,4,3],[6,5,5,0],[7,6,1,0],[8,3,3,2],[9,2,1,0]]) (87,[[6,5,5,1],[7,5,3,2],[7,6,1,1],[9,2,1,1]]) (88,[[6,6,4,0],[8,4,2,2]]) (89,[[6,6,4,1],[7,6,2,0],[8,4,3,0],[8,5,0,0],[9,2,2,0]]) (90,[[6,5,5,2],[6,6,3,3],[7,4,4,3],[7,5,4,0],[7,6,2,1],[8,4,3,1],[8,5,1,0],[9,2,2,1],[9,3,0,0]]) (91,[[5,5,5,4],[7,5,4,1],[8,3,3,3],[8,5,1,1],[9,3,1,0]]) (92,[[6,6,4,2],[7,5,3,3],[9,3,1,1]]) (93,[[6,5,4,4],[7,6,2,2],[8,4,3,2],[8,5,2,0],[9,2,2,2]]) (94,[[7,5,4,2],[7,6,3,0],[8,5,2,1],[9,3,2,0]]) (95,[[6,5,5,3],[7,6,3,1],[9,3,2,1]]) (96,[[8,4,4,0]]) (97,[[6,6,4,3],[6,6,5,0],[7,4,4,4],[8,4,4,1],[8,5,2,2],[9,4,0,0]]) (98,[[6,6,5,1],[7,6,3,2],[7,7,0,0],[8,4,3,3],[8,5,3,0],[9,3,2,2],[9,4,1,0]]) (99,[[7,5,4,3],[7,5,5,0],[7,7,1,0],[8,5,3,1],[9,3,3,0],[9,4,1,1]]) (100,[[5,5,5,5],[7,5,5,1],[7,7,1,1],[8,4,4,2],[8,6,0,0],[9,3,3,1],[10,0,0,0]]) (101,[[6,6,5,2],[7,6,4,0],[8,6,1,0],[9,4,2,0],[10,1,0,0]]) (102,[[6,5,5,4],[7,6,4,1],[7,7,2,0],[8,5,3,2],[8,6,1,1],[9,4,2,1],[10,1,1,0]]) (103,[[7,5,5,2],[7,6,3,3],[7,7,2,1],[9,3,3,2],[10,1,1,1]]) (104,[[6,6,4,4],[8,6,2,0],[10,2,0,0]]) (105,[[7,6,4,2],[8,4,4,3],[8,5,4,0],[8,6,2,1],[9,4,2,2],[10,2,1,0]]) (106,[[6,6,5,3],[7,5,4,4],[7,7,2,2],[8,5,4,1],[9,4,3,0],[9,5,0,0],[10,2,1,1]]) (107,[[7,7,3,0],[8,5,3,3],[9,4,3,1],[9,5,1,0]]) (108,[[6,6,6,0],[7,5,5,3],[7,7,3,1],[8,6,2,2],[9,3,3,3],[9,5,1,1],[10,2,2,0]]) (109,[[6,6,6,1],[8,5,4,2],[8,6,3,0],[10,2,2,1],[10,3,0,0]]) (110,[[7,6,4,3],[7,6,5,0],[8,6,3,1],[9,4,3,2],[9,5,2,0],[10,3,1,0]]) (111,[[6,5,5,5],[7,6,5,1],[7,7,3,2],[9,5,2,1],[10,3,1,1]]) (112,[[6,6,6,2],[8,4,4,4],[10,2,2,2]]) (113,[[6,6,5,4],[8,6,3,2],[8,7,0,0],[9,4,4,0],[10,3,2,0]]) (114,[[7,6,5,2],[7,7,4,0],[8,5,4,3],[8,5,5,0],[8,7,1,0],[9,4,4,1],[9,5,2,2],[10,3,2,1]]) (115,[[7,5,5,4],[7,7,4,1],[8,5,5,1],[8,7,1,1],[9,4,3,3],[9,5,3,0]]) (116,[[7,7,3,3],[8,6,4,0],[9,5,3,1],[10,4,0,0]]) (117,[[6,6,6,3],[7,6,4,4],[8,6,4,1],[8,7,2,0],[9,4,4,2],[9,6,0,0],[10,3,2,2],[10,4,1,0]]) (118,[[7,7,4,2],[8,5,5,2],[8,6,3,3],[8,7,2,1],[9,6,1,0],[10,3,3,0],[10,4,1,1]]) (119,[[7,6,5,3],[9,5,3,2],[9,6,1,1],[10,3,3,1]]) (120,[[8,6,4,2],[10,4,2,0]]) (121,[[7,6,6,0],[8,5,4,4],[8,7,2,2],[9,6,2,0],[10,4,2,1],[11,0,0,0]])

Thursday, February 15, 2018

[hjyeziee] Energy cost effectiveness of thermonuclear bombs

Suppose we wish to extract useful energy, probably generate electricity, from thermonuclear explosions by blowing up H-bombs.

The motivation is, both magnetic and inertial confinement fusion might be too difficult to ever be commercially successful.  However, if we want fusion, we do have a proven way of doing it now.

How cost efficient is it, counting only the cost of the consumables?  Unfortunately the things that go into an H-bomb, and their costs, are closely guarded military secrets.  Weapons-grade uranium or plutonium for the primary stage.

Bigger bombs are probably more efficient: the fuel of the secondary stage (and later fusion stages) are likely much cheaper than the primary.  Tsar Bomba proved large bombs do work, though we might want to go even larger for cost efficiency.  How large of a nuclear bomb can be built before hitting difficult engineering or science problems?

Of course, harnessing the huge amount of energy released by the bomb in the very short amount of time is a mechanical engineering challenge.  But internal combustion engines harness explosions all the time.  Bullets and Project Orion are other examples of the energy of explosions harnessed to do useful work.  We imagine an extremely large blast chamber, large enough so that the explosion doesn't destroy it, then heat is collected on the outer surface to generate electricity.  How large does the blast chamber need to be?  Because of the inverse-square rule, there's definitely a size that's large enough. I'm guessing it might be comparable in size to the planet.  What material should the blast chamber be filled with?

If the nuclear explosion could be made anisotropic, a shaped charge, then this could make the blast chamber easier to build, for example, building a hemisphere instead of a giant sphere.

Is the largest hurdle to doing this the mechanical engineering difficulty of containing the blast and extracting energy, or the political / national security traditions of keeping nuclear weapons and information about them off limits to everyone?  What's stopping us from having unlimited energy?

Tuesday, February 13, 2018

[cjauuaxv] Big-game pumpkin hunting

Create a business which offers clients the opportunity to shoot a pumpkin, which gives a satisfying explosion when hit.  Wealthy clients are given the opportunity to shoot very large pumpkins which are rare and difficult to grow, with very powerful guns.  They give a very large and very satisfying explosions.

Of course, this is modeled on trophy hunting of big animals, including how the hunting outfit lures the animal close enough so the wealthy client has an easy shot.  A very large pumpkin could be just as rare as big game -- you might have to wait years for the opportunity to shoot one.  Shooting a stationary pumpkin is approximately a similar amount of challenge as shooting an animal lured in front of you, perhaps more exciting because the pumpkin gun might need to be larger.  Finally, its dramatic explosion makes the pumpkin much more satisfying as a kill.

Inspired by

[rkgjmqgg] Partial peer review

A peer reviewer of a scientific paper might have replicated the experiments and analysis and got the same results.  Or, looked over the Methods and deemed them sufficiently clear that the experiment could be replicated, and checked the analysis.  Or something else, perhaps just endorsed that the author is a trustworthy and diligent person.

Accompanying a publication, it would be nice if it were declared how far the peer reviewers went to, well, review.  This would help readers decide how much to trust the paper.

Monday, February 12, 2018

[wyhqwyhd] Spherical pool

Consider playing pool on the surface of a sphere.  Balls travel along great circles, geodesics.

Place some barriers on the sphere for the balls to bounce off of, and some pockets in which to sink.

Ambitiously, build it for real: only one ball is possible, which balances exactly on top of the spherical "table".  When the ball rolls, the table rolls the opposite direction underneath keeping the ball balanced precisely on top.  This continues until friction brings the ball to a stop.  There needs to be some precise tracking.  We need some way of imparting initial rotation to the billiard ball: I think hitting it with a traditional cue will simply knock the ball off.

[vxwwbbud] Learning foreign language songs

Learn -- memorize -- how to sing a large number of songs in one foreign language.  Is this an effective way to learn a foreign language?  The brain will organize the songs into patterns for easier memorization, especially common patterns of form words, idioms, and grammatical constructs, and store them in a way suitable for quick retrieval.  This is exactly language acquisition.

It could be a fun way to learn a foreign language, if you like to sing, if the songs are good.  You'll probably be inspired to learn the meanings.

What songs are good, covering the useful parts of a language?

[rkwktjlk] Time advantage for black

In chess, white seems to have a slight advantage due to first move.  Try to balance it out with a time advantage given to black.  What are the time advantages that are good at various time controls?  Fixed multiplier or something higher order?

Sunday, February 11, 2018

[tnnhqckp] Best poker deck

Poker can easily be modified to decks with a different number of cards per suit and a different number of suits.  Probably want to recalculate probabilities and reorder hand types by probability, including 5-of-kind or greater.  Which deck produces the best game?  How do you define "best"?  Perhaps the ability to segregate humans to many levels of play.

Decks can have more interesting structure than a two-digit number is some base.  The Hoffman-Singleton graph has many structures around the number 5, which happens to be the number of cards in a poker hand.  Previously.

[ievqdaab] Planet-sized Rube Goldberg

Actions in one place emit signals which are received elsewhere, setting off further actions that release signals.  Ambitiously, the sequence circles the earth and repeats.  What kind of cycle time can you achieve?

Internet is of course the obvious global communication network, though others exist: bouncing radio signals off the moon.

[hbrtsvpe] The turn of the wheel

Fairly straightforward framework for a story: People are drinking.  Hookups happen.  Some of those hookups turn into relationships.  Some of those relationships break up.  They take solace in drinking, and then the whole cycle repeats.

Idea from elsewhere.

[uibxcdhp] Speed does not matter in congested traffic

Assuming people are obeying guidelines for safe following distance (a false assumption in reality), then the speed cars are traveling makes no difference in the maximum flux of the highway: a car passes a given point every 4 seconds.

[dahvviwo] Recruiting PreCheck

TSA PreCheck seems like a bad idea because terrorists get to move second.  A person initially completely unaffiliated with terrorism gets approved for PreCheck because they are completely unaffiliated with terrorism.  Terrorists can then target their recruiting to already PreCheck-approved people to get a device through the more lax security measures of the PreCheck lanes, perhaps another shoe bomb because PreCheck does not require X-raying shoes.

Is it even good security theater?  Does the sight of certain people going through more lax security make people feel safer?

[uxttlofp] Plentiful day care and reeducation camps

What would happen if society provided child care, or more broadly child raising support for free as much as the parents wanted until the child reaches adulthood?  Parents can take as little or as much involvement in "parenting" as they wish; government picks up any and all slack.

Perhaps many parents would take very little involvement in their children, essentially putting their kids up for adoption.  Then, the state, given nearly full control over (some) children's lives and development, might deploy procedures that homogenize the next generation of the population, for better or for worse.

What could possibly go wrong?

[emihqled] Acronyms in ideographic languages

Acronyms in languages like Japanese and Chinese can be far richer than those with small alphabets.  Inspired by 全 日本 食品 株式会社 (All Japan Food Corporation), which can be abbreviated 全日食 which could be interpreted to mean "total solar eclipse".  This is similar to an acronym spelling out a real word in English, but the space of real words possible in a small number of characters is much larger with kanji.

[nuyxqahp] Sofa maze

Depict a solution to Moser's Moving Sofa Problem, e.g., the Gerver Sofa, moving around a No Left Turn maze.

Subtleties: is U-turn permitted?  If so, the sofa changes parity in what type of turn it can make.  If the maze has infinitely thin walls, then I think the Gerver Sofa cannot navigate hairpins, two right turns immediately in a row.  This suggests a new problem, the largest sofa which can make that turn.

Romik's ambidextrous sofa can travel through an ordinary maze with no turn restrictions, though it may still have problems with hairpins.

Moser's Moving Sofa Problem can easily be generalized to other angles (e.g., a maze using an underlying equilateral triangular lattice), and probably more dimensions.

[zdcnrpzx] Maze of twisty little passages

The simplest maze-generating algorithms generate mazes with straight passages and only 90-degree turns.  Create an algorithm which permits many more angle possibilities and curved passages (of many and varying curvatures).  There will likely be wasted space because the passages no longer fit nicely next to each other.


[bnrtnzfv] 3D maze with ramps

Consider constructing a maze based on a grid of square rooms with doors between them.  Adjacent connected rooms can differ in height be a small amount, perhaps an amount small enough to have a ramp that is easy to go up or down, or a short flight of stairs.  It is then possible to have several rooms stacked on top of each other, making it a 3D maze.  Go to the room directly above by traveling though a series of rooms whose small level changes sum to the height of a room.  This is in contrast to a typical 3D maze which requires traveling vertically straight up or down.

Lots of hints possible: 3D coordinates of where you are, windows in which you can see into but not travel to adjacent not-connected rooms.

Minecraft or VR.

Other tessellations possible.  It doesn't even have to have an underlying tessellation.

[ainsclnz] Two types of satire

There are two distinctly different kinds of satire, one which makes the audience feel good about themselves and the other which makes the audience feel uncomfortable about themselves.

Some publications / compilations do a mix of both.

Probably only the former can be commercially successful.

[xzwxflda] Spaces matter in Markdown

Enumerate the situations in Markdown in which whitespace matters.  Inspired by this gotcha with unordered lists.

* one
* two
* three
* four



The latter gets rendered as a paragraph of alternating italicized and non-italicized text: one two three four.

Previously, on other special characters which may trip you up in Markdown.

[xvdfqlev] Dialects with armies

A language is a dialect with an army.  Among countries whose language is named after a different country, list them by size of their army.

  1. American
  2. Brazilian
  3. Mexican
  4. ...
  5. Moldovan
  6. ...

It's not that bad an idea to define a language in terms of an army: it means there's enough mutual intelligibility including shared culture that one can practically organize an army with it.  Curiously, the word Urdu means "army".  Urdu is Hindi with its own nuclear arsenal so is of course a separate language.

Go further and define the normal or standard dialect as the one belonging to the country with the largest army.  Hugh Laurie speaks American with an Englandish accent, but can lose the accent and speak normally when playing an American character.

[bducdsxa] Gravity on non-spherical planets

Given a hypothetical non-spherical planet, especially one wildly different from a sphere, compute its gravity at its surface.  One way to depict it is drawing arrows on the surface saying which way and how fast a drop of water would flow.  Compute basins and watershed boundaries.  It is also possible that gravity is such that water might be pulled off the surface in certain locations.

[yczsdnxs] Neural net backdoors

A vendor provides you with a neural network system that identifies bad entities, for some definition of "bad".  Does it contain a backdoor?  It is currently very difficult to look at a neural network and determine what is does.  How would one design a difficult-to-detect backdoor into a deep neural net system?  How would one prove a system doesn't have a backdoor?

Of course, the ultimate example of such a "system" is a double-agent human whose brain is the neural network.

Saturday, February 10, 2018

[wwhkkicd] Emoji as heraldry

A cumbersome but arbitrarily easily extensible framework for encoding emoji is to index them (at least, new ones) by arbitrary text strings instead of numeric code points.  The font rendering agent has access to the text string and can render it appropriately, perhaps using NLP AI to generate an emoji image for text it has never seen before.  Such emoji (probably) cannot have interesting properties like specifying alphabetization, but usually that's not needed for emoji.  It is a little strange that a large number of characters as data go into producing a single displayed character, but this is similar to characters composed of multiple combining characters or joined by zero-width joiners.

This is similar to heraldry, in which the text describing an image is canonical; different artists may render the text in different ways.

The Unicode consortium can establish standard characters for the beginning and end markers of the descriptive text strings and standards for what goes in them (what language?  What encoding?  All caps?  Are emoji recursively permitted within the descriptive strings?).  Then, a decentralized process happens with people inventing text strings describing emoji and font designers inventing how to render them.  Standardization can then do things like the following: Identify popular emoji supported by many fonts and used commonly.  Popular emoji can be assigned code points to conserve data usage.  Multiple different text strings describing the same thing could be combined into one code point.  Identical text strings describing different things (homonyms?) could be separated out to different code points.

[fcgqncyr] Typing Latin

What portion of the world (among the subset that uses computers) use computers with keyboards with which it is difficult to type the Latin letters A-Z?  I suspect very few: a keyboard with local orthography will also have additionally marked the Latin alphabet for ease of typing web and email addresses.

What portion of the computer-literate world does not know the Latin alphabet?  By "know", probably something like: given a web or email address in print, they can type it on their computers.  How much of a barrier to access to computing is learning the Latin alphabet?

If the barrier is low, then maybe we don't have to push so hard to do internationalization, at least in some areas.  Inspired by IDN, Punycode, and attacks against it, though domain names are not necessarily a domain we should decrease efforts at internationalization.  If a user remembers only how a website is spelled in the local orthography, he or she will need a search engine to find the ASCII address.  This puts search engines in the position to be gatekeepers.  In contrast, if the user can directly type the address in the easier-to-remember local orthography, DNS is a decentralized system for which it is far more difficult to be a gatekeeper.

[ztqmslvh] Psycho XXX

Consider creating a porn parody of Hitchcock's Psycho.  Easy: just expand the peephole scene and cut out the rest of the extraneous filler.  The motel should get a sexually suggestive name -- oh wait it already has one...

Was Hitchcock creating straight-up porn?  In order to do so, he would have had to comply with the Hays Code of the time.  Of course, don't show too much skin, which Hitchcock complied with: definitely far less skin than today's standards of porn, though he was pushing the boundary at the time.  More subtly, the Code roughly required that only bad people do anything sexual.  Being the subject of a peep show is sexual: Marion Crane had been established as a dishonest office worker who steals a tremendous amount of money from her firm.  This plot point had always seemed irrelevant: the suspense and horror would have worked just fine without it.  However, it does make sense if Hitchcock was needing to comply with the Hays Code.  What else about the movie is there just to avoid the whole thing being censored?  Maybe all the suspense, mystery, and horror -- the things that make it one of the greatest films of all time -- was just extraneous filler to distract the censors from the real point of the film.

Tangentially, it would have been cute if Tom Cassidy reappeared later in the film.  Upon learning his money had been stolen, he subverts expectations and does not get angry.  He simply pays out another 40K (this time with a check), staying true to his earlier statement that the earlier cash 40K was "money he could afford to lose".  He even assumes the best of Marion Crane, that she is putting stolen money to good use to "buy off unhappiness", and even takes some pleasure in helping someone he fancied accomplish that.  He sends a private investigator after her not to recover the money but out of genuine concern for her well-being after her mysterious disappearance.  (Of course, such a plot would not be Hays Code compliant.)

[nxqmwkox] Death Star morality, or lack thereof

It is cute that Rogue One established (via kyber crystals) that the Death Star is just an oversized lightsaber (or maybe a lightsaber is a miniaturized Death Star?), explaining away with the same "magic" two of the more scientifically implausible technologies in Star Wars (though the Death Star is not that implausible).

Curiously, before firing the Death Star at full power, there is depicted no philosophical hand-wringing about whether mortals should wield such a power akin to a god.  Depict such conversations, or explain why not.  Such conversations did occur before detonating the first atomic bombs.

Some possibilities why not: The Emperor is a god, so firing his weapon to do godlike tasks is perfectly normal.  The Empire had been regularly destroying planets already, perhaps with Base Delta Zero or telekinesis by the Emperor or Darth Vader, so this is nothing new, just a slightly new way to go about it.  The history of ancient superweapons is still very much present in people's minds, so firing a Death Star feels like firing an old firearm, nothing godlike.  The Emperor is doing vast Battle Meditation to prevent subordinates from thinking such thoughts.  (The Emperor may have been doing Battle Meditation to organize workers to build the thing, so this is another Sith technology involved in the project, another reason why nothing like it had been built until a Sith came to power.  The technology of labor organization is reminiscent of later civilizations expressing wonderment at the labor organization needed to build the pyramids.)  The Empire is deeply atheistic (perhaps due to its high level of technology) so does not believe that there are powers that only gods should have.

Friday, February 09, 2018

[fksvzxxv] 60 redundant connectors

A dodecahedral device interfaces with the outside world by plugging into a pentagonal socket.  All faces work with any of the 5 rotations of a face.  There are therefore a total of 60 interfaces (icosahedral symmetry), one for each fifth of a face.  Make them all redundant, because the interface is often the most fragile part of a device, so having many copies is good.

Motivation is the transfer interface of a highly reliable data storage device.

Less elegantly, it could simply have many ports (even more than 60), perhaps arranged on a grid on a face, each to which a cable may be connected, e.g., KVM.

[bapjmsrb] Better numerals

Design some numerals for 0 through 9 so that the symbols depict the cardinality or ordinality of the number.  Best is if the value can be decoded from the visual appearance of the numeral, but next best would be if the ordering of two numerals can be easily seen visually, perhaps in complexity of the symbol.

A few possibilities:

This first one is inspired by runes.  Let 0 and 1 be special characters, represented by their current symbols, a circle and a vertical bar.  Be careful about serifs on 1.  The remaining 8 numbers, 2 through 9, are represented by a vertical bar with short horizontal lines or loops (like the letter P) hanging off of it. A horizontal line represents +1 and a loop represents +2.  The vertical bar implicitly represents a start value of 1.  There can be up to 4 loops (2 on each side of the vertical bar), signifying the digit 1+4*2=9.  This number looks like a butterfly.  The lesser digits are butterflies with fewer wings or one wing replaced by a stick.  There only needs to be at most one horizontal bar.  We should standardize the positions of the loops and the bar for each digit.

For 10 distinct digits we could do something combinatorial with 2*5.  We could also go larger and (generally) not use digits greater than 9, though they could be used for larger bases.  12=4*3, 16=2^4 look attractive.

If we special case 0, then we only need to design 9 digits, doing something combinatorial with 3*3: a stack of 2 items, each with 3 possibilities.  If we special case 0 and 1, we only need to design 8 digits, 2^3: a stack of 3 items, each with 2 possibilities.  We need to be careful that none of the combinatorial digits look like the special case digits.

We did a survey through Wikipedia of writing systems whose numerals depict the number or at least made some sense in ordering based on visual appearance:

  • Counting rods
  • Japanese and Chinese for 1 2 3 only
  • Roman
  • Aegean
  • Babylonian
  • Chuvash
  • Kaktovik Inupiaq
  • Mayan

[odxhzxko] Source diffs and commit messages teach

Looking at a source code diff and its corresponding commit log message or ChangeLog seems like a good way to slowly learn computer programming in a low-pressure environment.

Adding this feature to a software package manager should be a high priority given the importance of having a more coding-literate populace.

[ebpjoocq] The Death Star is realistically buildable

Use a Nicoll-Dyson beam powered by a Dyson swarm around a star much brighter than the sun, e.g., Deneb.  Either focus the beam and precisely aim it from afar, or just drive the star, swarm, and beam generator to the target with a Shkadov thruster, the latter also requiring no technology we don't currently have.

Star Wars's Death Star's hyperdrive is unknown technology requiring unrealistic science; its superlaser is not. This proposed Nicoll-Dyson beam is certainly not the size of a small moon; it has the mass of a large star and size of a planetary system.  However, "giant sphere" is a roughly correct shape for a structure built around a star.

Moving a star with a Shkadov thruster unfortunately takes millions years which has both the problems of keeping the generations of crew focused on the task for that long and bright stars with their short lifetimes might go supernova before reaching the target.  In fact, it might even be a challenge to build the Dyson swarm within the lifetime of any star with energy output high enough to vaporize a planet in a few seconds.

So this superlaser is probably not practical as a weapon, but it might be useful as a toy: blow up nearby planets for fun just like the did in the movies (recreate the effect, as the Mythbusters do).

Inspired by Isaac Arthur.

Tuesday, February 06, 2018

[ikjtaeuy] A few popular foreign-language songs

  • Despacito - Spanish
  • 강남스타일 (Gangnam Style) - Korean
  • Dragostea Din Tei (Numa Numa) - Romanian
  • Neunundneunzig Luftballons (99) - German
  • Garota de Ipanema (Girl from Ipanema) - Portuguese
  • 上を向いて歩こう (Sukiyaki) - Japanese
  • Tu Vuò Fà L'Americano (sampled in We No Speak Americano)- Neapolitan
  • Очи чёрные (Dark Eyes) - Russian

[zfevsaab] Circular wipe

Consider the iris wipe between two slideshow frames with the next image becoming visible from the edges first.  The center, presumably the most important part of the current image, persists the longest.

Inspired by: we can't see detail in moving images.  Slides sliding is wasted time.

[syetklhk] Weight change due to stress

Some people gain weight when under stress; other people lose weight.  Which people do which and why?

[hipkucuc] Emacs pinky

People complain of Emacs pinky in having to press the Control key often but generally do not complain about having to press the Shift key often.  Why not?  I suspect Shift is pressed just as often as Control if not more so.

[izvsgyut] A whole circle in a piece

Circles are neat because seeing any portion of the arc is enough to uniquely determine the radius and center.  This is not true for other shapes. For regular polygons with small numbers of sides, we need to see the regions around at least 2 vertices, which are only a small parts of the whole perimeter.  Most of the perimeter of a polygon is a line, completely useless for telling anything about the polygon.

[dqelykfe] Accidentally a word

In languages not so dependent on the positions of words in a sentence, can you more easily recover from accidentally omitting a word earlier in the sentence?

[qzjsuabg] Yale vs Chicago speech

The differing policies and philosophies between the University of Chicago versus Yale University conveniently allows naming them.

Yale-style policies: safe spaces, triggering speech forbidden or required to be labeled.

Chicago-style policies: free speech.

Both spawn weapons for devious political purpose.  In Chicago-style, the content of the speech could matter less than the political position it represents: use triggering speech to exclude certain groups.  In Yale-style, use the punishment mechanism (or threat thereof) against certain objectionable speech to exclude certain groups for whom that kind of speech forms their identity.

Which policy is good when and for what purposes?  Probably depends on the self-qi levels of the listeners.

[cnpvmelm] Kinesis key remappings

Some key remappings I've used on the Kinesis Classic Ergonomic keyboard:

Logical ESC to where the physical Tab key is, which is where it was on the keyboard that the vi editor was designed for.

Tab to where the Delete key is (left thumb cluster) because I type it often for command completion and indentation.

Delete to Escape key, completing the 3-cycle.

Super key (Windows key) to where Caps Lock is for use as the modifier key for XMonad.

Sometimes I get around to moving Capslock to where the Super Key was in the Keypad layer.

[msquaaah] Precedence of equality and boolean operators

Some expressions to measure the relative precedence of equality versus boolean operators, in a language like C where 0 and 1 are false and true.  The first of the easiest to remember.

  • 0 == 0 && 0
  • 0 == 0 || 1
  • 0 == 1 || 1
  • 0 == 1 && 0

[kpkkdeyc] A dinghy is not an aircraft carrier

Depict a series of predictably disastrous unsuccessful attempts to land a plane on various sized boats, each time concluding, "We're going to need a bigger boat."  Not sure what the punchline should be.


[rxwvezsq] Francis

Deadpool catches up with Ajax after a year of hunting, attempts to rudely address him as Francis, but Ajax is not offended, in fact he goes by that name nowadays. "It's a fine name: Francis Bacon, Francis Crick, Sir Francis Drake the greatest pirate who ever lived, oh and that awesome and dashing villain in that superhero movie that just came out who has a change of heart about his name..."

(Were all those Frances knighted?)

Maybe poke fun at identity politics.

[xfbvnjxv] Astroturfing further from the center

Organize a political movement that deceptively suggests to right-wing politicians that they should move even further to the right.  This would put right-wing politicians in a quandary with both outcomes beneficial to the left:

They can heed the mostly fictitious ultra-right, moving their platform further right.  This will erode their support from real people in the center right, which they will pay for in the next election (assuming they don't destroy the country before the next election).

Or, they can regard with suspicion any seemingly far-right grassroots support, which will also cause them to ignore some actual far-right grassroots support.  This will cause the politician to move toward the center.

Are the politicians fooling the people or are the people fooling the politicians?  Tricky is if the movement to create a fictitious ultra-right involves manipulating actual suggestible people join and support the ultra-right.

Of course, this could also be done in the opposite political direction, though the right wing currently seems more vulnerable to such tactics.

[awrabqaz] Muses and dwarves

One class of supernatural beings, muses, inspire people.  But inspiration is not enough: another class of supernatural beings deal with the seemingly more mundane and thankless tasks of creating a environment around the inspired one wherein which the inspiration can be taken to the fruition of an actual work of art, science, etc...

[mylfjyle] Avoiding government by the low self-qi

Design a government robust to some of its members having low self-qi.  Dictatorship is of course terrible for this: a dictator having a bad day will cause a lot of harm.  Even if the method by which government members are selected -- the way people acquire power -- tends to filter out those with low self-qi, people will occasionally have bad days.

In parallel, design an environment around those with power that maintains a high level of self-qi for them, so they don't commit harm with their power.  Such social environmental engineering is applicable beyond just government, anywhere where power of exercised.

We can also look at this descriptively: successful governments are those which have found a way to accomplish the above tasks.

[ambrpygb] Park your car near Harvard Yard

Modify the famous sentence from "in" to "near".  "Near" gets pronounced distinctively in the Boston accent and makes the sentence semantically possible to do.

[dyvqyimt] What men want

Both as a literary trope and probably also in the real world, a mentor, perhaps a bitter feminist, advises a naive girl that men are pigs and are interested in only one thing: to have sex with her.

Rarely (at least when following the trope) does the girl then respond with the critical question, "Why?"

That is, "Why does the act of having sex with me dwarf in pleasure and satisfaction all the other ways I can improve, entertain, or be useful in the life of a boy or man?  What is going on inside the his mind that having sex with me has so much value to him compared to everything else?  How did he come to have and to keep maintaining such a system of values?"

In the real world (as opposed to literature) do girls ask those questions?  If not, why not?  (That was a meta question.)  Do you assume you already know the answers?  (If so, what are the assumed answers?  Are your answers accurate?)  Do you not care what the answers are?  In the context of a social class boundary between the girl and the pig-like lower class men, no, she does not care to know more about those below her.

They might be uncomfortable questions to answer.

Monday, February 05, 2018

[aamkajwr] Worst packing convex shape

What convex shape has the worst (least) packing density?

In two dimensions, the answer is conjectured to be the regular heptagon.  Currently the best known packing of regular heptagons achieves a density of 0.89269.  However, if a denser packing of regular heptagons is discovered, in particular, one with density greater than 0.902414, then the heptagon will no longer be the worst shape: there exists a "smoothed octagon" whose highest density packing is proven to be that number.

One way to look for better packing of a regular heptagon is simulated annealing.  Or actual annealing followed by determination of crystal structure if you can create a regular heptagonal molecule.

In going from the regular hexagon to the regular heptagon, we go from the best to conjectured worst packing shape.  After the regular hexagon, do the regular polygons steadily increase in packing density approaching the packing density of a circle?

The question could easily be generalized to a sphere or other manifolds.  What convex shape of unit area requires the largest sphere to fit N copies on the sphere?

Friday, February 02, 2018

[dtethwpm] Unicode hexadecimal

Create a block of Unicode characters denoting hexadecimal digits.  This would be helpful in marking a string intended to be hexadecimal data which happens not to have any digits 0-9, avoiding it from being interpreted as a regular word: DEAD BEEF, etc.  It would also be helpful in avoiding a hexadecimal string which happens not to have any digits A-F from being interpreted as a decimal number.  Previously.

Of course, with some programs using these characters but some not, it will be a mess, kind of reminiscent of curly quotes versus 7-bit clean quotes.

We could similarly have a block of 256 Unicode characters representing bytes.  The visual appearance of a byte character could be its value in hexadecimal, similar to placeholder characters seen when a font does not have a character.  The ability to encode binary data inline with text seems intriguingly potentially useful, though I'm exactly sure for what.  It accomplishes a similar purpose as MIME and base64.


There are clock characters for representing base 12 starting around U+1F550, and even sort of base 24 using the half-hour clocks.  Base 6 has dice at U+2680.  I Ching symbols: U+2630 (base 8), U+268a (base 2 and base 4), U+4DC0 (base 64), U+1D300 (bases 3, 9, 16, and 81, but not 27).  6-dot Braille U+2800 (base 64), 8-dot Braille U+2840 (base 256).  There are exactly 100 characters in the domino tiles block U+1F030.  Fractions around U+2150 and elsewhere, intriguingly including 0/3.  Playing cards with 14(!) cards per suit at U+1F0A0.

There are a great many pairs of characters that could encode binary, e.g., ASCII ACK and NAK.

Are there any other bases commonly in use?  Base 60 in time and angles.  Base 20 seems likely.

Wednesday, January 31, 2018

[kfnmlrlk] Incompetence appearing as malice

Enumerate situations in which incompetence can strongly appear to be malice.  Gray area.

[luapmttv] Room temperature cheese

Cheese tastes radically different depending on what temperature it is.  Fats can melt in your mouth, like chocolate, releasing flavor dissolved in fat if not too cold.

Cheese sliced thin or shredded absorbs ambient heat quicker.

[xifpmmhs] Sukiyaki

The lyrics of the song Sukiyaki 上を向いて歩こう are powerfully bittersweet.  As it reached high popularity in the English-speaking world, were the listeners aware of the meaning of the lyrics?  In 1960s America, there were probably very few resources for translation from Japanese.  Does the sentiment carry through in the music even if you do not understand the lyrics?

The name Sukiyaki is of course ridiculous.  Much better would have been Hitoribocchi -- a word used repeatedly in the song -- meaning "lonely".

[cipzvuew] Other applications of the modularity theorem?

Are there other nice easily accessible corollaries to the Modularity Theorem other than Fermat's Last Theorem?

[nmcihzfy] More majuscule

We can add the digits 1 through 9, omitting zero which is difficult to distinguish from the letter O, to the list of capital (uppercase) letters, yielding 45.  Use lining figures (uppercase numerals) not text figures.

We assume that font and resolution sufficient to differentiate OQ can also differentiate 1I 2Z 5S 6G 8B etc.

There are also lowercase letters with ascenders but I don't feel they work so well in this collection.  In some fonts, J and Q (and maybe more) have descenders.

For base 45, it might be better to use zero and omit capital letter O so that the symbols can use a natural order: numbers, Latin letters, Greek letters.


Tuesday, January 23, 2018

[oemprfgv] Voronoi on a sphere

Voronoi diagrams on a plane always have regions of uncomfortably infinite area.  A Voronoi partition of a sphere does not have this problem.  Also, the torus does not have this problem.  Inspired by an animation of Voronoi partitions of moving points.

The Delaunay triangulation remains finite.

[csmdfofy] Sample only 1% of users

If you are collecting personal information to improve your service or software, uniformly sample only 1%.  Your statistics will remain valid, but the collected Big Data is unlikely to be misusable in a targeted attack against a particular person: any particular person has a 99% chance of having escaped your mass surveillance.

Services and software providers can advertise the percentage that they sample and compete with each other for the lowest percentage.  They can get certifications from trusted third parties that they are only collecting 1%.

[dglnfsxs] Carlsen improving others' endgame play

The story goes, Magnus Carlsen won a lot of chess games from drawn endgames which motivated his peers to improve their endgame play, so he doesn't win as many in that way anymore.  Test whether this story is true by objectively measuring the quality of moves of his opponents.

Previously, on impact.

[cgbeflff] Reordering chaconnes

Can the variations of a chaconne or passacaglia be reordered?  If so, this offers a relatively easy avenue to change or improve a piece.

[upivculb] Website checklist

How does your web page look in a very narrow browser window?  Do paragraphs of text reflow?

How does your web page look with the browser's default colors changed to white text on black background?

How does your web page look with JavaScript turned off?  Does it need to look as bad as it does (for JavaScript games, yes; for textual content, probably not)?

[ftzqznpc] Eulogy for Java applets

With the removal of NPAPI after Firefox 52, Java applets will no longer run.  This is unfortunate as Java was one of the few languages that had put some thought and effort into a security model and sandboxing, in contrast to the giant mess that is Javascript.  (Unclear whether Java's security model was any good.)  There were a great many fine Java applets (games, graphics demos) which did nothing but draw onto a canvas, requiring no additional privileges: it is a shame those will no longer run.

Can Java applets be resurrected in the brave new world without NPAPI?  Probably involves compiling a JVM into Javascript or Webassembly.

Also dead are Wolfram Demonstrations.

[qxyxntvs] List of escapes

Markdown requires backslash-escaping the following 15 characters: \ ` * _ { } [ ] ( ) # + - . !

LaTeX requires being careful about the following 10: $ # % _ { } ^ ~ \ &

HTML requires using an entity to denote the following 2: < &

C strings require a backslash escape for the following 2: \ "

This blog recently switched to Markdown-based composition.  Things may go wrong if I forget which characters need to be escaped when.

[fnkttzox] Inspirations and imitations

Great pieces of art inspire derivative works, many more loosely than in the legal copyright sense.  Enumerate them for some art considered great.

Great pieces of art are usually built on ideas from previous art.  Enumerate them.

What came before; what came after.

[stqbglit] Keyboard layouts

Assume Dvorak's idea of all vowels on the home row on one side is a good idea.  AEIO should go directly under the fingers (where ASDF are), and U, the least common vowel, goes at G.

Some common letter should go where semicolon is now.  Or maybe backspace if you don't have a keyboard that can put it on the thumb.

Other common consonants on the right hand home keys.  TH being two of them seems like a good idea.

Remaining letters go in alphabetical order across the keyboard to make them easy to find, though there are many ways to do this.

[rahqenfa] Permuting a keyboard layout

Create keyboard layout which can be learned gradually as modifications to QWERTY: a series of small changes which can be learned over time.  Swaps of 2 keys are the smallest type of change, then cyclic 3-permutations.

Avoid any key from participating in multiple (successive) permutations.  Only a subset of permutations of the original layout are reachable.

[sgxtsbmn] Spectating blindfold chess

The audience watches a projected board with pieces while the players play blindfold chess.  What annotations on the audience's board would be interesting, perhaps hinting at where players might make a blindfold-induced mistake?

How long a piece has been there?  Where has it been recently?