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
Dominoes involves standing them on end in long lines so that when the first tile is toppled, it topples the second, which topples the third, etc., resulting in all of the tiles falling. By analogy, the phenomenon of small events causing similar events leading to eventual catastrophe is called the domino effect. Arrangements of millions of tiles have been made that have taken many minutes, even hours to fall. For large and elaborate arrangements, special blockages (also known as firebreaks) are employed at regular distances to prevent a premature toppling from undoing more than a section of the dominoes while still