# How Domino Is Played

Domino is a family of games played with rectangular, flat tiles. The tiles are normally twice as long as they are wide. Each tile has an arrangement of spots or pips, like those on a die, on one side and is blank or identically patterned on the other. Each domino is distinguished from other tiles by its number of pips, which is used to indicate the value of the tile. The dominos are played face up in a line of play, either end to end or across. As the tiles are placed in the line, a configuration of tiles is formed, called the layout or string. This determines how the game is played and who makes the first play.

Dominoes are used for a variety of games, both simple and complex. The most common types of domino games are blocking and scoring games. Other kinds of domino games include games of chance or skill, adaptations of card games, and even solitaire-like games.

A typical domino set contains a total of twenty-four tiles with matching numbers on both sides. However, these sets can be “extended” to provide more unique combinations of ends, thus increasing the number of pieces available for playing. The most popular extended sets are double-nine (55 tiles), double-twelve, and double-15. There are also a few larger sets, such as double-21.

Once the domino set has been expanded, players take turns placing dominoes in a line of play. This configuration of dominoes is known as the layout or string, and determining how it is played determines the rules of the game. The player who plays the first tile may be referred to as the setter, the downer, or the leader. Once the player has chosen his or her tile, it is placed in the center of the layout, facing up. The next player must then match the tile by placing his or hers on top of it in the proper position.

As the dominoes are played, they form a line of play that runs from left to right or across the layout. In many games, the first tile played must be adjacent to the left edge of the line of play. Depending on the rules of the game, it may then be followed by a single or double domino that matches the number of the adjacent tile. In some games, the first double played is a spinner and can be played on all four sides; in others, the double must be played on two sides.

When a domino effect occurs, there is usually uncertainty associated with the data and models used to identify the effect. This is due to the fact that no model or simulation can consider all possible scenarios at once. However, a few methods have been developed for quantifying this uncertainty. This article focuses on two of these methods: Bayesian network technology and Monte Carlo simulation. The authors show how these techniques can be used to estimate the probability of a domino effect.