Another case is the outline of the behind the foot spot where the balls are in straight pool, since the outline of this area is strategically important throughout the game. In artistic pool, lines may be drawn between opposite sights putting a grid on the playing surface. Other grid patterns are used in various forms of balkline billiards. A recent table marking convention, in European nine-ball, is the . Carom billiards tables Pocketless carom billiards tables are used for such games as straight rail, balkline, one-cushion billiards, three-cushion caroms, and artistic billiards. Dimensions Regulation 10 × 5-foot carom billiards tables have a playing surface (measured between the noses of the cushions) of with a 5-millimetre allowance. The standard height range of the table, measured from the playing surface to the ground is between 75 and 80 centimetres. Bed The slate bed of a carom billiard table must have a minimum thickness of 45 millimetres and in tournaments recommended heating temperatures is , which helps to keep moisture out of the cloth to aid the balls rolling and rebounding in a consistent manner, and generally makes a table play faster. A heated table is required under international carom rules and is an especially important requirement for the games of three-cushion billiards and artistic billiards. Pool tables A pool table, or pocket billiards table, has six – one at each corner of the table () and one at the midpoint of each of the longer sides ( or ). Dimensions Pool tables come in different sizes, typically referred to as , , , or tables. In all cases, the table is rectangular with a ratio (e.g. ). There are only two sizes approved for tournament play by the International Olympic Committee–recognized sport governing body of pool, the World Pool-Billiard Association (WPA), and its various regional and national affiliates; under the world standardized rules of pool, these are the and models. For a table, the playing surface (the dimensions between the noses of the cushions) measures with a (3.2 mm) margin of error for either dimension. For an , the playing surface measures , with the same inch variance allowed. In the UK as well as a number of other British Commonwealth and European countries, the typical pool table is a , although tables for the pub and home market are also common. These are the sizes used by internationally standardized blackball and