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2023-03-21 16:08:07

John Carlos Baez on Nostr: Wow! People have been seeking this for many years! David Smith, Joseph Myers, Craig ...

Wow! People have been seeking this for many years! David Smith, Joseph Myers, Craig Kaplan, and Chaim Goodman-Strauss have finally found a single shape that can only tile the plane aperiodically - that is, in ways that don't form a repeating pattern.

But there's a catch: you need to use both this shape and its reflected version. Is this necessary? Or is there a single shape whose translated and rotated versions can tile the plane, but only aperiodically? This is an open question!

Penrose's famous 'dart' and 'kite' are a *pair* of tiles whose translated and rotated versions tile the plane, but only aperiodically.

In 1966, Robert Berger showed there is a collection of shapes that can tile the plane if and only if there's a proof of Goldbach's conjecture in Zermelo-Fraenkel set theory.

But actually he did much more: for any Turing machine he constructed a finite set of shapes that can tile the plane if and only if that Turing machine halts!

For more on the new result:

• An aperiodic monotile, https://cs.uwaterloo.ca/~csk/hat/

For more on Berger's result:

• Wang tile, https://en.wikipedia.org/wiki/Wang_tile

There is no shape in the plane, homeomorphic to a disk, whose translated (not rotated) versions tile the plane, but only aperiodically. But there's been a recent surprise in higher dimensions:

• Rachel Greenfeld, Terence Tao, A counterexample to the periodic tiling conjecture, https://arxiv.org/abs/2211.15847

Thanks go to and for correcting an error in a previous version of this post.

Author Public Key
npub17u6xav5rjq4d48fpcyy6j05rz2xelp7clnl8ptvpnval9tvmectqp8pd6m