[ebzgthrf] Dihedral angles in real life

If the earth were, say, a regular icosahedron, there would be ridges at edges.  Build such a ridge at human scale.  This should be easy.

Depending on exactly how gravity works, the ridge could be symmetric, approached from both sides at the same slope, or horizontal with a downhill slope on the other side from the point of view of the observer (gravity abruptly changes on the other side, probably for a game).