Dominoes domino sets commercially available are double six (with 28 tiles) and double nine (with 55 tiles). Larger sets exist and are popular for games involving several players or for players looking for long domino games. The number of tiles in a set has the formula formula_1 for a double-"n" set. The most popular type of play are layout games, which fall into two main categories, blocking games and scoring games. The most basic domino variant is for two players and requires a double-six set. The 28 tiles are shuffled face down and form the "stock" or "boneyard". Each player draws
Schläfli double six formed in this way are all in turn intersected by another line, "a". The twelve lines "a" and "b" form a double six: each line "a" has an intersection point with five of the other lines, the lines "b" for which "i" ≠ "j", and vice versa. An alternative construction, shown in the illustration, is to place twelve lines through the six face centers of a cube, each in the plane of its face and all making the same angles with respect to the cube's edges. A generic cubic surface contains 27 lines, among which can be found 36 Schläfli