Hat is a 9-cell still life that was discovered independently in 1971 by several Life enthusiasts and named by Charles Corderman.
It (as well as similar still lifes such as mirrored table) can be used as an eater (in particular, a rock) stabilizing the twin bees shuttle. The mechanism has some similarities to snake-type eaters.
The loop and eleven loop can be seen as the long and long long versions of the hat. Orthogonally lengthened versions of the hat are also possible still life components (a long³ version appears in Cthulhu), though they are not still lifes of their own.
Hat is the twenty-fifth most common still life in Achim Flammenkamp's census, being less common than trans-boat with tail but more common than boat tie ship. It is also the thirty-third most common object on Adam P. Goucher's Catagolue.
All strict still lifes with a population of 20 or fewer cells, as well as all oscillators and spaceships with 16 or fewer cells, are known to be glider-constructible. A glider synthesis of this object can be found in the infobox to the right.
- 9.1 at Heinrich Koenig's Game of Life Object Catalogs