Myers Polyhex Tiles

This shape is a world record holder you need 20 tiles before it will tile the plane periodically (10 up to symmetry). It fits together in an amazing variety of ways but can easily block itself. Making it a fun puzzle.

The tiles were found by a massive computer search by Joseph Myers. Look for this and other puzzling shapes at: http://www.srcf.ucam.org/~jsm28/tiling/

The idea to make physical tiles was originally from Chaim Goodman-Strauss: http://www.mathbun.com