Hat Tile

A 13-sided polykite, the hat, that tiles the plane but never periodically. The first aperiodic monotile; Spectre later dropped the reflections.

Hat Tile: A 13-sided polykite, the hat, that tiles the plane but never periodically. The first aperiodic monotile; Spectre later dropped the reflections.Hat Tile: A 13-sided polykite, the hat, that tiles the plane but never periodically. The first aperiodic monotile; Spectre later dropped the reflections.

About this pattern

Smith, Myers, Kaplan & Goodman-Strauss, 2023

Hat Tile, aperiodic tiling, drawn by GART: A 13-sided polykite, the hat, that tiles the plane but never periodically. The first aperiodic monotile; Spectre later dropped the reflections.
Hat Tile · CC BY 4.0

David Smith found the 13-sided hat in 2023; Myers, Kaplan, and Goodman-Strauss proved it is an aperiodic monotile: one shape, no periodic tiling, reflections allowed. The Spectre, later that year, tiles without mirrors.

Monotile
Thirteen sides, one tile. Copy it, reflect it, and the plane fills, never periodically.

Behind the mathematics

David Smith

Discovery

British shape enthusiast who discovered the hat, the first known single tile that forces an aperiodic covering of the plane.

Joseph Samuel Myers

Proof and construction

Mathematician and tiling researcher who helped prove that the hat monotile admits tilings but can never tile periodically.