I want to read about a certain mathematical concept but cannot recall the word for it. Then I remembered it's described in «Schild's Ladder» by @gregeganSF … but where is my copy??

That which is ponderous has

Of the 924 ways to choose six segments out of twelve, these 306 are connected.

@bathsheba @henryseg Have you had any dealings with Shapeways since it came back to life?

All this talk of aperiodic tilings provokes a question: can a sphere be tiled, with a single shape, with no nontrivial symmetries? I'm not asking for a tile that forces asymmetry.

Math(s)-wise, I'm in an awkward position: most laymen don't understand what interests me, and I don't understand what interests real mathematicians.