Appendix - npincomplete/tetris GitHub Wiki
Terminology
Tetromino
A tetromino is a polyomino made of four square blocks. Tetrominos come in seven shapes, all of which can be rotated and then dropped. The seven one-sided tetrominoes are I, O, T, S, Z, J, and L. The spelling "tetromino" is standard among mathematicians.
Polyomino
A polyomino is a piece made of two or more square blocks, where all blocks are connected through full coincident edges.
- A free polyomino is one that may be translated (moved about), rotated, or reflected.
- A one-sided polyomino is one that may be translated or rotated.
- A fixed polyomino can only be translated.
Polyominoes come in several sizes:
- 2 blocks make a domino
- 3 blocks make a tromino
- 4 blocks make a tetromino
- 5 blocks make a pentomino
Polyominoes are often named by a Latin letter that resembles the shape of the polyomino. For instance, an "I" has all its blocks in a straight line, and a "T" consists of an "I" tromino with one or more blocks in a straight line connected to one side of the center of the "I".