Domino is a game of skill and luck. It is played by one or more players and involves matching up the pips on the open ends of dominoes, which are called spots. There are many different games that may be played with dominoes, and each game has a slightly different set of rules. Some games are block or scoring games, while others allow for pass-and-byes and tricks. Many of these games can be played with just two people, but many are designed for four or more players.
In most domino games, a domino must be placed so that its two matching ends are touching. This can be done in a horizontal, vertical, or diagonal position. If the domino is a double, it must be placed so that its two matching halves are touching and both sides of the domino are facing the same direction.
If a player places his or her domino in the wrong way, the domino must be recalled and placed correctly. If this is not done before the next play, that player will be considered to have played out of turn. This may be punished by a penalty or forfeiture of points.
Most dominoes are arranged in a line on the table, and each player attempts to make the most accurate plays possible by forming chains of tiles that will eventually come to rest on a line of zero or more points. Some players may also arrange dominoes into 3-D structures such as towers and pyramids. The most complex domino arrangements can take several nail-biting minutes to fall. These kinds of displays are sometimes put on by domino builders, who compete to create the most elaborate chains and reactions before an audience of fans.
The physics of a domino chain is fascinating. A single domino has a high center of gravity, but it only needs to be slightly tipped forward to start a chain reaction. A row of hundreds of dominoes can be lined up and tipped over all at once, and the results are amazing to watch.
When playing domino, the order of play is determined by drawing lots or, if not in a fixed seating arrangement, by determining who has the heaviest domino (see Heaviest Tile below). A player who draws his or her first hand according to the rules of the game will then begin to place tiles. After each player has drawn his or her hands, the players draw any additional tiles he or she is permitted to take from the stock for his or her dominos, depending on the game being played. Those extra tiles may then be passed and bought (see Passing and Byeing below) during the course of that game, or returned to the stock before other players begin drawing.