Domino is a game played with a set of small rectangular wood or plastic blocks, each marked with dots resembling those on dice. The game involves building a chain of these tiles, one end of each touching another, to form a line of play. Each player takes a turn placing a domino edge to edge with another in the line of play, until it is complete or the dominoes run out. Whether the line of play is straight or curved, a sequence of tiles falling over is created when the first domino is knocked over.

A person who loves to create elaborate domino setups and then watch them fall is a domino artist. Lily Hevesh, 20, is a domino artist with millions of YouTube subscribers and many spectacular setups to her credit. She says physics is the key to her work, especially gravity. “When you stand up a domino upright, against the pull of gravity, it stores energy in that position,” explains Stephen Morris, a physicist at the University of Toronto. When that domino is knocked over, it transfers much of its potential energy into kinetic energy, which causes the next domino to tumble and create a chain reaction.

In some games, part of the score for a winning player comes from counting the number of pips remaining on the dominoes in the losers’ hands at the end of their hand or the entire game. This can be done by examining each domino in the line of play or by counting only one end of a double (i.e., a 4-4 counts as only four points). Some players may agree to count both ends of the same double as one end of the line of play.

The first tile to be placed in a domino chain is called the lead. Its partner, the second tile, is then positioned on top of it. The two tiles should be positioned so that the matching ends are adjacent and, in case of a double, touch fully at both sides. This pattern of placement is sometimes referred to as the line of play, the string, or the layout.

After determining who is to make the first play (see Order of Play above), some players may draw additional tiles from the stock that they are permitted to buy (see Passing and Byeing below). These are added to the ones they have drawn in their hands and, depending on the rules of the game being played, may be played at any time later in the same turn. The player who made the first play is referred to as the setter, the downer or the lead.

A person who is a domino master has the ability to build an intricate chain of dominoes that will take several nail-biting minutes to complete. This skill requires not only a love of the game, but an eye for detail and an understanding of the science behind it all.