Diamond polyomino

A diamond is a polyomino that is orthogonally directed from all four directions and thus has no outside concavities. They form a rough diamond or lozenge shape, giving them their name. When a diamond has no punctures, is is called convex. Convex polyominoes have a perimeter equal to their boundary box. By definition, they are crescents.

Symbol

Dir40\textrm{Dir}_{4}^{0}

Regex

ru(ru)*(lu)*ld(ld)*(rd)*

Polyomino list

ru2luld2rd
5
6
7
8
ru3luld2rd
7
8
ru3luld3rd
8