A domino is a small rectangular wood or plastic block with a number of dots resembling those on dice. It can be used to play a game of chance or as a tool to build a structure. The most common use is as a model to teach children about counting and probability. For example, children can create a sequence of events such as a train accident, earthquake, or robbery by placing a single domino on a line of other dominoes and then moving each one in turn so that the next is pushed down on top of it.
Dominoes are available in a variety of colors and styles, although most are made from polymer materials such as PVC or ABS plastic. Some are molded from natural clay or even frosted glass. Other types are crafted from different types of woods such as birch or beech; from other natural or semi-natural materials such as marble, limestone, soapstone, or sandstone; or from metals including brass and pewter. Historically, sets of domino were also made from bone or silver lip ocean pearl oyster shell (mother of pearl, or MOP), ivory, and dark hardwoods such as ebony. These sets are often considered more elegant and more valuable.
In most domino games a player must play all of his or her tiles before the other players. If a player does not have an opening double, then he or she must draw new dominoes from the stock until an opening double is found. The player with the highest-numbered double leads, followed by the next highest, and so on. The first player to reach a final score wins the game.
Some of the most popular domino games are ones where a player must make all of his or her matches by matching the pips on the open ends of the dominoes. The player must continue to match the pips in this fashion until one of his or her dominoes does not have any more matches and cannot be played. The resulting line of matches is called the line of play. Various rules for establishing this are followed depending on the game.
A skillful player can sometimes increase his or her score by playing a double to the end of a line of play. This is called a spinner, and the player may receive one or more points when this occurs. If the player is the first to reach a specific total such as 61, he or she will receive a bonus.
When a large group of dominoes is laid out in a circle or other shape, it can take several nail-biting minutes for the whole thing to fall. This is because each domino has inertia, a tendency to resist motion until a force acts upon it. Then that force, a slight nudge for example, can cause the entire sequence of dominoes to tumble over in a chain reaction. Hevesh uses this technique to create stunning displays for movies, TV shows, and events, and she once helped set a Guinness World Record for the most dominoes in a circular arrangement: 76,017.