A domino (plural: dominoes or dominations) is a small rectangular wooden or plastic block with one or more sides bearing a number of spots resembling those on dice. Its edges are normally twice as long as its width, and the number of spots (also called pips) on each end determines the value of the tile. Dominoes are typically played by two or more people who take turns placing tiles on a table in such a way that the matched ends form lines of tiles and/or totals of line lengths and tile halves.

Dominoes are used to play many games of skill, chance, and strategy. Most of these involve blocking or scoring with a line of tiles, but there are also several game variants that use the tiles as building blocks, and some are puzzles where players place the tiles based on arithmetic properties of the pips. The word “domino” also has a figurative meaning referring to an event that leads to a chain reaction.

When Hevesh sets up a domino display, she follows an engineering-design process similar to the one that architects and engineers follow when designing buildings or bridges. First, she decides on the theme or purpose of the installation. Then she brainstorms images or words that might fit that theme. Finally, she creates a model of the final design using cardboard or another material and tests it for stability.

The most popular domino games are positional, in which the player takes a turn by putting a domino edge to edge against an existing tile. The player must then either match the value of that tile’s pips, or make it equal to some specified sum. The most common domino set has 28 tiles, and there are also progressively larger “extended” sets that add more matching possibilities by adding pips to some of the ends.

A common extension is double-six, which increases the maximum possible number of pairs of matching ends to 63. There are also a few other types of extended domino sets, including double-nine and double-15.

In addition to the traditional blocking and scoring games, dominoes are used in many other types of games, including solitaire and trick-taking games. They are played all over the world, but they are most popular in Latin America and among Inuits (Eskimos) who appear to have adopted Western games to help them circumvent religious bans on gambling.

Domino games are also often used to help children develop their motor skills. The large, heavy stones make good toys for promoting the development of hand-eye coordination. They are also a great tool for developing counting skills.

In the political arena, a domino effect is an analogy for a cascade of events that result in a certain outcome. It is a term that has been applied to both actual and hypothetical series of events, but it is most commonly used to refer to the effect produced when one event causes a chain reaction that leads to the desired outcome.