Scrabble of points for each lettered tile is based on the letter's frequency in standard English; commonly used letters such as vowels are worth one point, while less common letters score higher, with Q and Z each worth 10 points. The game also has two blank tiles that are unmarked and carry no point value. The blank tiles can be used as substitutes for any letter; once laid on the board, however, the choice is fixed. Other language sets use different letter set distributions with different point values. Tiles are usually made of wood or plastic and are square and thick,
Scrabble six and nine games are played each day. There are also clubs in the UK and many other countries. There are a number of internationally rated SOWPODS tournaments. During off hours at tournaments, many players socialize by playing consultation (team) "Scrabble", Clabbers, Anagrams, Boggle, Words with Friends, Scramble with Friends and other games. Maven is a computer opponent for the game, created by Brian Sheppard. The official "Scrabble" computer game in North America uses a version of Maven as its artificial intelligence and is published by Atari. Outside North America, the official "Scrabble" computer game is published by Ubisoft. Quackle