#### How Do Dominoes Work?

A domino is a rectangular block, thumb-sized and marked with from one to six pips (dots) on each face. A complete set has 28 such pieces. They are used to play games of chance or skill in which the goal is to line up and fall dominoes in a long row without them falling over. The first domino to fall begins a chain reaction that can continue until all the pieces have fallen.

When a player sets down a domino, it stands on its edge with its pips facing up. The other side is blank or identically patterned to the one facing up. As the player takes his turn, he places a domino on the table, positioning it so that its matching end touches an existing domino on its own side or on the other side of the game board. The pips on each domino indicate its identity: the ones are numbered, the twos match, and the threes form an even number of dots.

The way the ends of the dominoes touch each other and the shape of the resulting chains provide much of the fun of domino. A domino must be played so that its matching ends are adjacent. It may also be placed perpendicular to a double, in which case the domino is positioned diagonally from the other side of the double. A domino played to a double that is already touching its matching end will cause the domino to form a snake-line shape across the top of the table.

As the first domino falls, most of its potential energy is converted to kinetic energy, the energy of motion. This energy then travels to the next domino. The force pushing on the second domino is stronger than the force that would have pushed the first domino, and so it overtakes the first one and knocks it over as well. And so on.

Nick’s method for making dominoes proved useful and popular, and his business flourished. He was able to develop more complex domino designs, and his manufacturing process for making them was perfected. Soon he was selling thousands of them every day to stores and schools across the country.

As Hevesh creates her mind-blowing domino installations, she uses a version of the engineering-design process. She makes test versions of each section of an installation, films them in slow-motion, and checks them for accuracy. Once she knows that each piece works as intended, she combines them into the final setup. The largest 3-D sections go up first, then she adds flat arrangements and finally the lines of dominoes that connect them all together. When she has finished, the result is stunning. Dominoes can be laid in straight lines, curved lines, grids that form pictures when they fall, stacked walls, and 3D structures like pyramids. The possibilities are endless, and each arrangement has its own unique challenge.