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"
Scrabble a player who goes out adds twice that sum, and his or her opponent is not penalized. Plays can be made in a number of ways (in what follows, it is assumed that the word JACK has been played on a previous turn; letters in parentheses represent tiles already on the board): Any combination of these is allowed in a play, as long as all the letters placed on the board in one play lie in one row or column and are connected by a main word, and any run of tiles on two or more consecutive squares along a