Mixed Angle
New Polyform Possibilities Using Mixed Angle Systems Previously, puzzles have tended to confine themselves to only one angle system. For example, the 12 pentominoes (pieces built of five squares) use only the 90° (“ortho-“) system, while Stewart Coffin’s “Snowflake” puzzle (pieces built of three or four hexagons, called “trihexes” and “tetrahexes”) uses a uniform 60° …