L Tetromino

The L is one of the seven tetrominoes, the four-square pieces that fall in Tetris. Three squares sit in a row with a fourth attached at one end, so the piece looks like the letter L. It has no symmetry, so each of its four rotations is a different placement on the board: there are four fixed L tetrominoes, as there are four J and four T, two each of I, S and Z, and one O, nineteen in all. The L is chiral. Its mirror image is the J, and on a flat board one cannot be rotated into the other, although as solid tetracubes the two are the same piece.