Carom billiards, sometimes called carambole billiards or simply carambole (and in some cases used as a synonym for the game of straight rail from which many carom games derive), is the overarching title of a family of billiards games generally played on cloth-covered, 1.5-by-3.0-metre (5 by 10 ft) pocketless tables, which often feature heated slate beds. In its simplest form, the object of the game is to score points or "counts" by caroming one's own cue ball off both the opponent's cue ball and the object ball(s) on a single shot. The invention as well as the exact date of origin of carom billiards is somewhat obscure but is thought to be traceable to 18th-century France.