a counterpart to a polyomino where the polygon used as the building block is an equilateral
a plane figure composed of a number of equilateral triangles joined by common edges
a polygon formed by joining equilateral triangles edge to edge
a union of unit area equilateral triangles where triangles meet along two entire sides
a figure composed of equilateral triangles joined by common edges. Some polyiamonds are rep-tiles and IFS attractors.
A polyiamond (also polyamond or simply iamond) is a polyform in which the base form is an equilateral triangle. The word polyiamond is a back-formation from diamond, because this word is often used to describe the shape of a pair of equilateral triangles placed base to base, and the initial "di-" looked like a Greek prefix meaning "two-".