Three-cushion billiards (sometimes called three-cushion carom, three-cushion, three-cushions, three-rail, rails and the angle game, and often spelled with "3" instead of "three") is a form of carom billiards, and one of the most popular and challenging cue sports in the world[citation needed].The object of the game is to carom the cue ball off both object balls and contact the rail cushions at least 3 times before the last object ball. A point is scored for each successful carom. In most shots the cue ball hits the object balls one time each, although hitting them any number of times is allowed as long as both are hit. The contacts between the cue ball and the cushions may happen before and/or after hitting the first object ball. The cue ball does not have to contact 3 different cushions as long as they have been in contact at least 3 times in total.