A didrafter is made by joining two 30°-60°-90°
triangles along equal edges, where the halves of a triangle's hypotenuse
may be used separately.
A didrafter is proper
if it can be placed on a polyiamond grid
so all its edges lie on the edges and medians of the grid cells.
Otherwise it is improper
Two or more polyforms are said to be compatible
if there exists a figure that can be tiled with any of them.
Here I present some compatibility figures
These are the proper didrafters:
These are the improper didrafters:
These figures are minimal. They are not necessarily uniquely minimal.
Last revised 2020-09-09.
Back to Pairwise Compatibility
Col. George Sicherman