Basis principle of scrabble. But, be warned, if you play the autobot (the computer), it cheats. Often, it hides your letters so that you don't see all the letters in your hand. If it can't play a word and you are winning, it freezes up forcing you to click out of it when you return to the game, it starts a new game with you instead of finishing out the old game. Dictionary isn't up to date. Tons of tech issues.