It is one-third of a regular hexagon.
A polygem is a figure made by joining gems on the polydrafter grid. The terms are due to Abaroth.
A Galvagni Figure is a figure that can be tiled by a polyform in more than one way—a kind of self-compatibility figure. Here I show minimal known Galvagni Figures for polygems. If you find a smaller solution or solve an unsolved case, please write.
See also Polygem Oddities.
Last revised 2023-03-25.