## The Domino Effect

The domino effect is a physical phenomenon that occurs when a series of objects, placed one on top of the other, are knocked over by a single impulse. As a domino falls, its potential energy is converted to kinetic energy—the energy of motion—and some of that kinetic energy is transmitted to the next domino in line, giving it the push needed to knock it over as well. This continues for every domino in the chain, until all have fallen.

Dominoes are rectangular pieces of material, generally made of wood or plastic, that have a number of pips—a pattern of dots—on each face. They are marked on one side with an arrangement of spots that correspond to those on a die, although some have no marks at all. A domino has two ends, a left and a right, and each end is marked differently: either a double or a single.

Many different games can be played with dominoes, but most of them fit into four categories: bidding games, blocking games, scoring games, and round games. Some dominoes are designed for artistic use, with straight lines, curved lines, grids that form pictures when they fall, or 3D structures like towers and pyramids. Others are intended for game play, with rules and objectives that govern how the tiles are laid out on the table.

Hevesh, who has built a global business on her mind-blowing domino installations, uses a version of the engineering-design process when creating her work. She begins by considering the theme or purpose of an installation, and then brainstorms images or words that might be appropriate to the design. She also calculates the number of dominoes she needs and the size of track that will be necessary to support her installation.

To determine seating arrangements in a multiplayer game, players draw a domino from the stock and then seat themselves according to their choice of seat, with the player who draws the heaviest tile making the first play. If a tie exists, it is broken by drawing new dominoes from the stock. In some games, the winner of the last game makes the first play.

In some domino games, the heaviest tile may be a double or a single. In most games, however, the first play must be a double, followed by a single if possible. The rest of the tiles remain in the stock until a player has used all his or her hands, at which time the remaining dominoes are reshuffled and the players draw new hands.

As each domino is played, it joins a line of play that runs across the table, with doubles being played lengthwise and singles being played crosswise. A player may make plays out of turn, but if a mistake is discovered before the next player makes his or her play, the misplayed tile must be recalled from the boneyard and replaced.