A domino is a small rectangular block of wood or plastic. People use them to play games in a variety of ways. Some children like to line them up in long rows and knock them down, while others build complex structures using them. Some people even make domino art, constructing elaborate lines of dominoes that form pictures when they fall. This has led to the expression domino effect, which means that one event leads to many more events in a chain reaction.

Dominoes can be purchased at most toy stores and in some grocery stores. They are also sometimes used in classrooms to help students learn about the principles of math and science. For example, a teacher might ask a class of students to find the largest number that will evenly divide the sum of all the numbers on a domino. Students can then work together to create a chart that shows how many dominoes should be placed in each box in order to achieve the desired result.

In addition to playing domino games, the pieces can also be used in classrooms to help students understand how the law of gravity works. In this way, students can see that a single action can have much larger—and sometimes catastrophic—consequences than initially expected.

When Lily Hevesh was 9, she started using her grandparents’ classic 28-piece domino set to make straight and curved lines. Soon she was creating domino art and posting videos of her creations online. Today, Hevesh is a professional domino artist who creates intricate designs for movies, TV shows, and events. Her YouTube channel, Hevesh5, has more than 2 million subscribers.

Hevesh’s creations require a great deal of patience and attention to detail. When she builds a large 3-D domino installation, she has to plan out each section carefully. To avoid mistakes, she makes test versions of the sections first and films them in slow motion to check for precision. Once she’s confident that the individual sections work well, she assembles them into the larger structure.

A physicist at the University of Toronto, Stephen Morris, explains that when Hevesh sets up her giant dominoes, she is creating a chain reaction by converting potential energy to kinetic energy. When the first domino is tipped over, much of that potential energy is converted to the kinetic energy of the other dominoes in the sequence, leading them to tumble over in quick succession.

Before beginning a game of domino, players must determine who will make the first play. This can be done in several ways, including drawing lots or placing the heaviest domino on the table. The player who makes the first play is sometimes referred to as the setter, the downer, or the leader. The order of play can also be determined by seating arrangement or, in some games, by “byeing” tiles from the stock (see below).

Some domino games are played with more than two players. Each player draws a number of tiles from the stock that are permitted for play, according to the rules of the game. The tiles are then added together and, if they can be played, are added to the dominoes in a player’s hand. A player may also choose to buy a domino from the stock, which allows him to skip a turn.