Domino is a family of games that involve the placement and manipulation of rectangular blocks called dominoes. A domino has a square face divided into two parts, each bearing from one to six spots, or pips, which differ in value. The number of pips on a particular domino determines its suit; the suit of a particular tile also determines the way in which that piece is placed on the table, whether it is laid side-ways or end-to-end. There are many variations of dominoes and their games, and each variation has its own name.
A domino is normally twice as long as it is wide, allowing it to be stacked in long lines. When the first domino in a line is tipped over, it causes the rest of the line to fall over, creating a pattern that can be quite elaborate. A person who can create such a pattern is often referred to as a domino artist.
Historically, dominoes were made from wood such as ebony or mahogany and carved with either painted or etched symbols. Today, however, domino sets are available in a variety of materials, including ceramic clay and plastics. Some sets are even molded from rock crystal and other precious stones.
The most popular type of domino game involves laying out dominoes in a chain. Each player begins with a certain number of dominoes and, in turn, places them on the table so that each end of a domino touches another matching end of a different domino. The resulting chain can be shaped as desired to form straight or curved lines, grids that build 3D structures and walls, or even a puzzle of tiles that fit together to form the shape of a human or animal.
Dominoes were first used as a gaming tool in China during the 1300s. Unlike the 28-piece European dominoes of today, Chinese dominoes were designed to represent every possible combination of two six-sided dice throws. Each domino therefore contained the pips from one die on half of its face and blanks on the other, or a mixed suit.
A physics teacher named Stephen Morris explains that when a domino is stood upright, it holds potential energy based on its position. When the domino falls, much of this energy is converted to kinetic energy and causes the next domino in the chain to tip over. This is the origin of the phrase the domino effect, which describes a series of events that result from one small trigger.
In the Block game, players take turns placing dominoes until a player cannot go anymore. At that point, the player raps the table and play passes to his or her partner. The winning pair is the partners whose combined total of pips on remaining dominoes is lowest. The Draw game, a variant of the Block game, works in a similar fashion but has an additional rule: players must draw from a separate pool of sleeping dominoes each time they lose their turn.