InvertedL

InvertedL is a term used in geometry and tiling to describe a shape that is the mirror image of the standard L-shaped polyomino. In polyomino terminology, it represents the chiral counterpart of the L shape and is most commonly identified with the J-tetromino in Tetris terminology. The basic invertedL consists of four unit squares arranged to form a right angle, with the elbow at the inner corner and the longer leg extending in the opposite orientation from the standard L piece. More generally, the term can refer to mirror forms of L-shaped polyominoes of higher orders.

In tiling and puzzle contexts, invertedL shapes are used to tile rectangles or other regions, often with rules about allowed orientations. Because they are chiral, the invertedL cannot be rotated into the exact same shape as the standard L without reflection, which has implications for counting tilings and exploring symmetry. Algorithms in combinatorial tiling frequently examine both invertedL and L pieces to determine how they can cover a region completely.

In visual design and education, invertedL shapes appear as modular blocks or icons, helping illustrate concepts of symmetry, chirality, and tiling strategies. They also serve as simple examples in geometry lessons about rotations and reflections.

See also: L-tetromino, J-tetromino, polyomino, tiling.