When you imagine a domino, what comes to mind is a long line of the little squares standing up, ready to fall with the slightest nudge. You may think of someone carefully setting them up in a neat and careful sequence, then flicking just one to create a cascade. This is how dominoes are used in many games, but they’re also often set up to form art and even structures like buildings and bridges. In fact, there’s a whole genre of domino shows where builders compete to set up the most spectacular, elaborate domino reaction or effect for an audience of fans.
Like playing cards, of which they are a variant, dominoes are designed to be held in one hand, with the other resting on the domino table. The dominoes are normally twice as long as they are wide and have an identity-bearing side that contains an arrangement of spots, called pips, and a blank or identically patterned side. The pips indicate the value of a domino, which is sometimes called its rank or weight. The higher the rank, the more valuable a domino is.
The most common domino games fit into four categories: bidding games, blocking games, scoring games, and round games. A number of variations exist for most of these, but in general the basic rules are the same. In any game, players take turns adding tiles to the domino chain by matching their pips with those of an open end of an already played tile. The winner of the game is the first player to get all his or her tiles into a line of play.
To start a game, each player draws an equal number of tiles for his or her hand. If a player draws more than he or she is entitled to, the excess is considered an overdraw, and the player must return the extra tiles to the stock and draw again. A player who plays out of turn must either recall his or her tile, or count the pips of all the losers’ tiles (including those in the hands of players who win) at the end of a hand or the game and add that amount to the winning players’ score.
In a political context, the term domino effect has been used to describe the way that one small event can cause a chain reaction of events that leads to an undesirable outcome. For example, President Dwight Eisenhower cited the domino effect in a press conference to explain America’s decision to offer aid to South Vietnam in an attempt to prevent Communism from spreading to other countries.
A domino has potential energy, which is based on its position, and kinetic energy, which is the energy it has when in motion. When you pick up a domino and stand it upright, lifting it against the pull of gravity, some of that potential energy is converted to kinetic energy — the force that causes the domino to fall.