A tetromino is a 4-polyomino. There are five free tetrominoes, seven one-sided tetrominoes, and 19 fixed tetrominoes. The free tetrominoes are known
as the T-tetromino, L-tetromino,
skew tetromino, square
tetromino, and straight tetromino, respectively.

The shapes were popularized in the game Tetris, developed by Alexey Pajitnov in June 1985.

## See also

Polyomino
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## References

Gardner, M. "Mathematical Games: About the Remarkable Similarity between the Icosian Game and the Towers of Hanoi." *Sci. Amer.* **196**,
150-156, May 1957.Gardner, M. "Polyominoes." Ch. 13 in
*Hexaflexagons
and Other Mathematical Diversions: The First Scientific American Book of Puzzles
and Games.* New York: Simon and Schuster, pp. 124-140, 1959.Hunter,
J. A. H. and Madachy, J. S. *Mathematical
Diversions.* New York: Dover, pp. 80-81, 1975.## Referenced on
Wolfram|Alpha

Tetromino
## Cite this as:

Weisstein, Eric W. "Tetromino." From *MathWorld*--A Wolfram Web Resource. https://mathworld.wolfram.com/Tetromino.html

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