What just happened? A group of mathematicians created a "new" polygon previously known to exist only in theory. It's a 13-sided shape that they dubbed "the hat," even though it only vaguely resembles ...

Infinitely many copies of a 13-sided shape can be arranged with no overlaps or gaps in a pattern that never repeats. David Smith, Joseph Samuel Myers, Craig S. Kaplan and Chaim Goodman-Strauss (CC BY ...