Convex Shapes from the 13 Didrafters

A didrafter is a polyform made by joining two drafters, 30°-60°-90° right triangles, at their short legs, long legs, hypotenuses, or half hypotenuses. Polydrafters joined on the polyiamond (triangle) grid are called proper polydrafters. Polydrafters whose cells depart from the grid are called extended polydrafters. Here are the 13 didrafters, proper and extended:

Below I show how to arrange the 13 didrafters to make convex shapes. The number below each shape tells how many tilings it has.

According to this page by Ed Pegg Jr., Wei-Hwa Huang was the first to arrange the 13 didrafters to form a convex shape. Ed adds that he does not know how many other convex shapes they can make. Neither do I.

Last revised 2020-06-09.


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Col. George Sicherman [ HOME | MAIL ]