Domino is a game in which a player tries to build a chain of dominoes on the table by placing tiles one at a time so that each has its matching end touching another tile in the line. A domino has a number printed on it, and the other side is blank or identically patterned. When a domino is placed, it may be called a set, down, or lead depending on the rules of the particular game. Each domino in the line of play can be joined to another by placing a tile on its open end, unless the game rules specifically require otherwise. A chain of dominoes is said to be “in a straight line” when the line of play is lengthwise and all adjacent dominoes have their matching ends touching. A chain in a snake-line configuration is called a cross-way pattern.
In the beginning of a domino game, each player draws the number of dominoes that he is allowed to take from the stock according to the rules of the game being played. These dominoes are then added to the ones in his hand, and he then begins playing them. In some games, a player may be allowed to buy tiles from the stock by paying the price specified in the game’s rules. When a player byes, he draws a single tile from the stock and adds it to his dominoes, but does not place it in the line of play.
When a domino is placed, it is said to be stitched up when its matching end is connected to a different domino. This can be done by placing a tile on its matching end, or by playing a double on top of it. The latter is often required in order to make a chain of a specific number, known as a spinner, and is done to advance the game by increasing its speed.
The way in which a domino is played determines the result of the game. The most common outcome is to win by achieving some sort of score from the total of the numbers on the ends of the dominoes in the line of play. A domino’s score is calculated by counting the number of dots on each of its two matching ends, or on both ends if it is a double.
In addition to being a fun way to pass the time, dominoes are a tool for building very intricate structures and patterns. In domino shows, professional builders construct very complex chains of hundreds or even thousands of dominoes that are stacked on end and then tipped over with the push of only one domino. This is what gives rise to the expression the domino effect, which refers to a simple action that causes a series of greater–and sometimes disastrous–consequences. Physicist Stephen Morris describes how, when you stand a domino upright against gravity, it stores energy in its position. When you then let go of it, the energy is converted to kinetic energy, which causes domino after domino to fall.