# Polyiamond

## Definition

"A polyiamond ... is a polyform whose base form is an equilateral triangle."
https://en.wikipedia.org/wiki/Polyiamond
"Connected combinations of equilateral triangles can be called triangular animals ..."
Polyominoes
Solomon W. Golomb
page 90
A polyiamond is a polyform whose base form is an equilateral triangle.

**THEOREM**
"... if a polyiamond tiles an equilateral triangle, it will also be a rep-tile."
https://en.wikipedia.org/wiki/Rep-tile#Rep-tiles_and_polyforms
Theorem: If a polyiamond tiles an equilateral triangle, then it's a rep-tile.
TODO: Proof (Is a proof necessary?)

Proof unavailable

## Proper subsets