A domino is a small rectangular wood or plastic block, with one face bearing an arrangement of dots or markings resembling those on dice. The other side is blank or identically patterned. Dominoes have been made of many different materials and can be carved, painted or molded. Some sets are made from natural materials such as bone, silver lip ocean pearl oyster shell (mother of pearl) or ivory. Others are crafted from polymers such as resin or clay. Still others, most commonly the traditional European style, are made from ebony and are thicker than those used for modern tiles. A single domino may be played in one of several ways, depending on the rules of a particular game. A player who plays a tile out of turn does so at his own risk. This is known as a misplay. If the player’s error is discovered before the next play, he must recall the tile and its chain of dominoes. Otherwise, the misplay stands and any score achieved on it is added to the player’s total. Once a player has a set of tiles, he determines where to seat himself at the table. In games with multiple players, this can be determined by lot. After the tiles are shuffled and rearranged, each player draws a number of pieces from the stock corresponding to his rank at the table. The player who draws the highest rank sits to the left of the other players. If a tie exists, the ties are broken by drawing additional pieces from the stock until each player has a seat. The first player begins the game by placing his first domino in the line of play. He may be referred to as the “setter,” the “downer,” or the “lead.” The term is used to distinguish him from other players who will follow his lead in playing a domino. Unlike the energy of a ball rolling down a hill, the energy of a domino cascade is all-or-nothing, and it flows down the line at a constant rate. This is because a domino’s energy is converted from potential to kinetic, or energy of motion, as it falls. Physicist Stephen Morris of the University of Toronto says that when a domino is stood upright, it stores some potential energy, or energy based on its position, but as it loses height and comes down, it converts to kinetic energy in an all-or-nothing pulse. Just as nerve impulses travel at the same speed in our bodies, regardless of their size, so does a domino cascade. This makes it easy for us to predict the effect of a domino on its neighbors. It’s also why dominoes have become an important tool in the study of particle physics. It’s hard to get a clear picture of how particles behave without understanding what happens when they interact with each other. The same principle applies to writing fiction, where the scene domino is a metaphor for the way a sequence of scenes influences its neighboring scenes.