Dominoes spots from one to six are generally arranged as they are on six-sided dice, but because blank ends having no spots are used, seven faces are possible, allowing 28 unique pieces in a double-six set. However, this is a relatively small number especially when playing with more than four people, so many domino sets are "extended" by introducing ends with greater numbers of spots, which increases the number of unique combinations of ends and thus of pieces. Each progressively larger set increases the maximum number of pips on an end by three, so the common extended sets are double-nine, double-12,
Game given number or multiple, or simply to play all dominoes from one's hand onto the board. Sets vary in the number of possible dots on one end, and thus of the number of combinations and pieces; the most common set historically is "double-six", though in more recent times "extended" sets such as "double-nine" have been introduced to increase the number of dominoes available, which allows larger hands and more players in a game. Muggins, Mexican Train, and Chicken Foot are very popular domino games. Texas 42 is a domino game more similar in its play to a "trick-taking" card game.