Scrabble have been sold worldwide and roughly one-third of American and half of British homes have a Scrabble set. There are around 4,000 Scrabble clubs around the world. The game is played by two to four players on a square board with a 15×15 grid of cells (individually known as "squares"), each of which accommodates a single letter tile. In official club and tournament games, play is between two players or, occasionally, between two teams each of which collaborates on a single rack. The board is marked with "premium" squares, which multiply the number of points awarded: eight dark red "triple-word"
Tile-matching video game game mechanic, rather than a distinct genre of games. The mechanism of matching game pieces to make them disappear is a feature of many non-digital games, including Mahjong solitaire and Solitaire card games. Jesper Juul traces the history of tile-matching video games back to "Tetris" and "Chain Shot!", published in 1984 and 1985. While both focus on pattern matching, they differ in important design points such as time pressure, tile manipulation and match criteria. A second generation of influential matching games – "Puzznic", "Columns", "Dr. Mario" and "Plotting" – was published in 1989 and 1990. Games building on "Dr. Mario"'s