A domino is a small rectangular wood or plastic block with a line down the middle that separates it into two squares marked by numbers resembling those on dice. There are many different games that can be played with domino, and some of them require more than one player. The most basic set contains 28 tiles, known as a double-six set, although larger sets containing more than 200 pieces are also available.
In order to play a domino game, the players must first agree upon how the tiles will be arranged on the table and what rules will govern play. These are generally described in a book called the Dominoes Manual or The Great Book of Domino Games. The most important rule is that each player must lay down a domino only when his turn comes up. Players may not hold back a domino for strategic reasons.
Once the initial agreement has been made, the tiles are shuffled and each player draws a domino from the stock. The player who draws the heaviest domino (based on the number of dots) will make the first play. If a tie is discovered, it is broken by drawing new dominoes from the stock until one player has the heaviest tile. Then that player will make the first play, unless the game’s rules state otherwise.
Most domino games are played by laying down tiles in a line on the table so that the pips on adjacent dominoes match each other. These tiles are called the line of play or layout, and they may be joined to each other either by placing a single domino with its open end against the matching number on another tile in the line of play or by playing a double with its open end against the number on another tile in the line of play.
Dominoes are normally twice as long as they are wide, and this configuration makes them easy to re-stack when not in use. Most dominoes have a round surface and are painted in bright colors that are easily visible under low lighting conditions. Some are also made of a more durable material, such as ceramic clay or frosted glass, that will not damage when dropped.
There are several variations on the rules of domino, and some games do not use all of the tiles in a given set. For example, some games have rules that specify whether or not a double is considered a spinner and which side of the tile it must be played on. Other games use a count, which is the total of all the pips on the ends of the line of play.
Besides the usual set of dominoes, there are special domino sets with a variety of unique shapes and patterns. These are sometimes used for artistic purposes, such as making curved lines or grids that form pictures when the dominoes fall. Other unique designs that can be made with dominoes include 3D structures, such as towers and pyramids.