Dominoes are flat, thumb-sized rectangular blocks, either blank or bearing from one to six pips (small dots resembling those on dice): 28 such dominoes form a complete set. They are used in games involving a sequence of dominoes, whereby each tile pushes the next domino to its tipping point. The resulting cascade can be simple or elaborate, such as a straight line or curved one or a grid that forms pictures when the dominoes fall.
A person who builds such arrangements, known as domino art or simply dominoes, can use a variety of materials and can be as creative as he or she chooses. The pieces can be glued together, placed on a base such as cardboard or wood, or stacked up into 3D structures such as towers and pyramids. Artists can also create intricate arithmetical patterns using the tiles, and can even design a track to play domino on, such as a train track or car park.
There are a large number of domino games, most of which fall into four broad categories: blocking games, scoring games, and strategy games. In addition, there are a number of other games that make use of the dominoes and do not fit into any of these categories.
For example, a domino may be used to mark an area of a board for play in a game such as chess, or it may be used as a betting token in a poker game. These are not considered to be true domino games.
When a domino is set up, it is called a layout or string, and the arithmetical order of the tiles in a particular layout is known as its “number.” The number is determined by the rules of the game being played. The number of tiles in a set is also important because it determines how many players can participate.
A player begins the first play of a domino game by drawing one of the tiles from the stock, as specified by the rules of the game being played. If there are more than one tile in the hand, the player must draw the tile with the highest number of pips.
Some sets of dominoes are made of different materials, such as silver lip ocean pearl oyster shell (mother-of-pearl or MOP), ivory, or a dark hardwood such as ebony, inlaid with contrasting black or white pips. These are generally considered to be of higher quality than polymer dominoes, although they can be more expensive.
Once a domino is pushed over, much of its potential energy converts to kinetic energy, the energy of motion. This energy then transmits to the next domino, providing the push needed to cause it to topple as well. As each domino falls, its movement ripples through the entire layout, creating a chain reaction that continues until all the tiles have fallen. This phenomenon is what gives rise to the term domino effect, referring to any action that triggers a cascade of events.