RPM is a word game played on a revolving board. The board is divided into 4 quarters. Each quarter has a top and bottom section. The object of the game is to form and capture words of 2 or more letters by placing letter tiles, one per quarter, as the board revolves. All players make their moves at the same time. The board makes exactly 5 revolutions before it is automatically stopped. This gives each player 20 opportunities to place his tiles. Colored tiles are used to capture completed words. - BoardGameGeek