The word domino is most often associated with the board game of the same name, but it can also refer to any kind of cascade of events that build on one another like a chain reaction. For example, a small change in the behavior of one person can set off an entire series of changes that affect many people. The concept of domino is similar to the Domino Theory, which is a theory that claims that once a country falls under communist influence, other countries will follow suit. The theory was popularized by the movie The Godfather and the song Domino by Steve Wariner.
A domino is a flat, thumbsized rectangular block with two sides that may be blank or have from one to six dots called pips or spots. Twenty-eight such dominoes form a full set. The term is also used for any of the many games played with such dominoes, usually by arranging them in lines or angular patterns. A domino is usually twice as long as it is wide.
When a player takes his turn, he places a domino, or tile, with its matching end to an existing domino, or piece, on the board. A piece may be placed perpendicular or parallel to the previous piece, but must touch it fully on one side and not on the other. Dominoes can be arranged in many different ways, but most of the time the pieces are arranged so that their adjacent ends match up with each other (e.g., 5 to 5, 12 to 12, or some other combination).
Once all the pieces are positioned, the domino chain is started by placing a domino with its matching end touching a piece already on the board. Other pieces are then stacked on top of the matching ends of the first domino, creating a snake-line pattern. Occasionally, the chains of dominoes are flipped over and used in a new way, such as to make a pattern or to create a different kind of game.
If a player cannot place a domino, he passes his turn. He can then pick up a sleeping domino from the table and use it for his next turn. The players continue taking turns until they run out of dominoes to pick up or until the pattern of dominoes has been completed in a manner acceptable to the game.
Aside from providing entertainment, dominoes are a great teaching tool. They help children learn the concepts of cause and effect as well as basic physics. They also help students practice their motor skills and math.
For writers, using domino as a metaphor can be helpful when it comes to explaining how an action in one scene can have a huge impact on the next. For example, when a character does something that violates the rules of his or her world, a writer must provide enough logic for readers to forgive the character’s actions and let them cascade naturally.