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"
Chess on a Really Big Board board for 3D chess would have 512 spaces, more than any large version of chess that had previously been invented; he then considered two-dimensional very large (or, in his word, "huge") chess games, mainly on the 16×16 board because such a board requires no non-standard equipment to construct, and while much larger than the 8×8 board, it was not so big as to make an unplayable game. This idea eventually came full circle in the development of the 16×16×16 three-dimensional version of Chess on a Really Big Board, which he called "impossibly large". The standard rules of chess apply, except