Double six dominoes is the most popular and also the traditional set of dominoes. It contains one unique piece for each possible combination of two ends with zero to six spots, and is known as a double-six set because the highest value piece has six dots on each end (the double six). The 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.