Directed polyomino
A polyomino is directed if every square in the polyomino can be described as a combination of moves in two directions (say, up and right) from a root square. By definition, it contains one corner square of its bounding box.
A polyomino is directed if every square in the polyomino can be described as a combination of moves in two directions (say, up and right) from a root square. By definition, it contains one corner square of its bounding box.