width of the table at from and parallel to the face of the . A semicircle with a radius of centred on this line within baulk forms in which the cue ball must be placed when breaking or after the cue ball has been or shot off the table. The position of four of are marked along the (lengthwise centre) of the table, perpendicular to the baulk line: the , from the ; the or , located at the midpoint between the bottom and top ; the or , located midway between the centre spot and the top cushion; and the or , located at the midpoint of the baulk line (and, thus of the "D"). Due to its obviousness, the brown spot is not always marked (neither are the unmistakable and , at the left and right intersections, respectively, of the baulk line and the "Ds curve. The exact placing of these markings are different on smaller tables, but proportional to the full-size model. Bed The of a good quality snooker table has a of slate and is covered with baize cloth, traditionally green, though many other colours are now available. The thickness of this cloth determines the table's (lack of friction) and responsiveness to , thicker cloths being longer lasting but slower and less responsive. The nap of the cloth can affect the run of the balls, especially on slower shots and shots played with applied to the . A snooker table traditionally has the nap running from the baulk to the top end and is brushed and ironed in this direction. Tables for other games Other types of billiard tables are used for specific games, such as Russian pyramid which uses a '12 ft by 6 ft' table (similar to a snooker table but with much smaller pockets), and Asian four ball which uses a pocketless 8 ft by 4 ft table. Games such as bagatelle often had more than six holes, including straight through the bed in the middle of the table, a feature still found in bar billiards and bumper pool. Novelty and home tables There are novelty billiard tables, often for pool, that come in various shapes including zig-zag, circular, and (especially for bumper pool) hexagonal. A circular table featured prominently in the 1972 film Silent Running. For the home market, many manufacturers have produced convertible billiard tables (in the broad sense) that double