Triomino

A triomino, also known as a tromino, is a 3-polyomino. There are two free polyominoes, (the same) two one-sided polyominoes, and 6 fixed polyominoes. The free polyominoes are known as the L-triomino (or right triomino) and straight triomino, respectively.

The L-shaped triomino is a rep-tile that can be dissected into four congruent smaller copies, each with half the linear dimensions of the original. This dissection is illustrated by Panckoucke (1749, p. xxx).

There is also a game called triomino consisting of 55 equilateral triangles, each containing three numbers from 0 to 5 at each vertex. Every combination of tiles is in the game, although those tiles with three different values are allowed to be arranged only in clockwise-increasing order.