Dominoes are a game-playing tool that are cousins of playing cards and allow for a number of games as well as tests of skill and patience. They were invented in the 1300s in China and have been a popular activity ever since. From dominoes used in professional gaming competition to the domino sets people set up and then knock over, domino is a versatile tool for game play that can be as simple or complex as the user wishes. The markings on a domino, known as pips, originally represented the results of throwing two six-sided dice. In modern times, however, a domino can be marked with any number of dots to indicate a specific result.

When a player drops a domino on its side, it causes the rest of the dominoes to tip over in a line. The entire line of dominoes then falls in a chain reaction that creates a large, often elaborate pattern or structure. Dominoes can be stacked to form straight lines, curved lines, grids that form pictures, or 3D structures such as towers and pyramids. Many people also use dominoes to create artistic pieces.

The first domino a person sets down on a board must be larger than the others to begin the chain reaction. If the first domino is smaller than the others, it will not be able to push other dominoes over, and the chain reaction will be stopped. This is why some players will place their pieces strategically on the board to make sure they are able to push over as many dominoes as possible.

In fiction writing, the idea of a domino effect is an excellent way to describe the effect one event can have on another. For example, if a character does something that is immoral or against societal norms, the writer must provide the logic that will give readers the right to accept the action or keep liking the character.

Using the domino effect in a scene can also help a writer create an effective plot. Whether the writer composes her manuscript off the cuff or takes time with a carefully detailed outline, a story needs to have a strong sequence of events that lead from one point to the next.

The traditional European domino set contains 28 tiles, sometimes called bones, stones, men or cards, that have a line across the face that divides it into square ends each marked with a number of spots, or dots. The backs of the pieces are blank or have a common design. The dominoes in a set must match in order to play the various games that can be played. Most people also own extended sets of dominoes that include additional ends with different numbers of spots. These extra end tiles increase the number of unique combinations to more than double the original number of dominoes in a regular set. A common extension is the double-nine set, which has 55 tiles. There are also sets that include double-12 and double-15.