## The Domino Effect

The domino effect describes a chain reaction that begins with one small action and leads to much larger and sometimes catastrophic consequences. It’s a good metaphor for any chain of events that could be disrupted by a single small event—it takes just a little nudge to set things off.

A domino is a small rectangular wood or plastic block that has a line in the middle and spots or dots resembling those on dice. It’s normally twice as long as it is wide. A domino has a value, which is indicated by the number of pips on each end. The more pips a domino has, the higher its value.

Many games can be played with a domino. The most common are blocking and scoring games. In these, the player places a domino onto the table so that its matching ends touch and thereby create a “chain.” Each subsequent tile placed must be touched by a previous domino, unless it’s a double—which means that it must be played perpendicular to the first double. As a result, the shape of the domino chain develops into a snake-line, as the players play around the limits of their playing surface.

Dominoes can also be used to build artistic structures. Creating intricate designs is called domino art. These can be straight lines, curved lines, grids that form pictures when they fall, or even 3D structures like towers and pyramids. The artist builds a model of the structure on paper before using the dominoes to build it. The artist may use different color dominoes to distinguish the different parts of the design.

A domino artist can create very complex designs, including entire rooms filled with dominoes that are arranged to look like the model. Hevesh, a professional domino artist, has built structures with up to 300,000 dominoes. Her largest projects take several nail-biting minutes to complete, but she says one physical phenomenon is essential to her success: gravity. When she knocks over a domino, its potential energy is converted to kinetic energy, which causes it to roll toward Earth. This energy is then transferred to the next domino and creates a chain reaction that can continue for miles.

Although dominoes are most often made of polymer, they can be crafted from natural materials, such as bone, silver lip ocean pearl oyster shell (mother-of-pearl), ivory, and a dark hardwood like ebony. These sets have a more interesting and classic appearance, and their heavier weight makes them feel substantial in the hand. In addition to their unique appearance, these natural materials have the advantage of being durable, which means they will last longer than plastic dominoes. They also tend to cost more than polymer sets. Some sets are made from a combination of these materials—for example, some feature the top half thickness in MOP or ivory with the lower half in ebony. This allows the dominoes to be matched together for a more attractive look. Other unusual materials used to make dominoes include marble, granite, and soapstone; metals, such as brass or pewter; ceramic clay; and frosted glass or crystal.