The domino effect is a concept used in popular culture to describe a series of events that start with a small, seemingly insignificant event that has a much larger—and sometimes devastating—consequence. The term is also used to refer to the game of domino, a tile-based game in which players build chains by laying down dominoes on end in long lines. When one domino in the chain is tipped over it triggers the next domino to tip, and so on. Many different games can be played with dominoes, and a person’s ability to build long and complex domino chains can be a significant factor in winning a game.
Dominoes are rectangular blocks that are normally twice as long as they are wide. They feature a line in the middle to divide them visually into two squares, with the identity-bearing side (also known as an “end”) bearing an arrangement of dots or spots, like those on a die, and the other blank or with no such markings. The number of spots on the end of a domino gives it its value, which may be different from one another or the same, and is also used to differentiate between dominoes in the same suit. The most common type of domino set has 28 unique pieces, with ends numbered from zero to six in the same way that the numbers on a dice are arranged.
Most of the games played with dominoes are positional, in which a player places a domino edge to edge against another so that their corresponding sides have matching values—for example, a single-zero domino is placed alongside a double-one, or a four-of-a-kind domino is placed alongside a five-of-a-kind. The resulting chain of dominoes can then be used to score points.
A variety of games can be played with dominoes, which are traditionally made from natural materials, such as bone, silver lip ocean pearl oyster shell (mother of pearl), ivory or a dark hardwood such as ebony, with contrasting white or black pips inlaid into them. More recently, sets have been produced from polymer or resins, as well as ceramic clay. These types of dominoes tend to be heavier than those made from natural materials, and can feel more substantial in the hand.
The most popular games of this type are called blocking or scoring games, and are often played with the standard double-six set of 28 dominoes. Larger sets are available for games with more than one person and for longer domino runs. In addition, there are a number of other games of a more abstract nature that can be played with a domino set. These games were once popular in some areas to circumvent religious prohibitions against the playing of cards, but nowadays they are largely obsolete. Some of these games involve the construction of patterns using a set of dominoes, and others are based on drawing specific combinations. In either case, the goal is to get a domino that matches a given pattern and then continue building on it, ideally until a player wins by having all of their dominoes matched.