thumb|upright=1.4|The 18 one-sided pentominoes, including 6 mirrored pairs
thumb|upright=1.4|The 18 one-sided pentominoes, including 6 mirrored pairs
A polyomino is a plane geometric figure, connected, formed by joining a finite number of unit squares edge-to-edge. It is a polyform whose cells are squares. It may be regarded as a finite and connected subset of the regular square tiling.
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).