Domino is a small, flat rectangular block used as a gaming object. It bears an arrangement of spots, or “pips,” like those on a die. A domino is typically made of rigid material, such as bone or plastic, and it can be affixed to a table in various ways. There are many different games that can be played with dominoes, and they usually fall into one of four categories: bidding, blocking, scoring, or round.

When a domino is set up and played, it can cause a chain reaction in which the next tile must match the open end of the previously played tile. This is called the “count.” Depending on the game, the count may be determined by the number of matching sides on the two dominoes, or by the total number of pips on the ends of a double played as a lead.

The players in a domino game take turns playing tiles. The player who makes the first play is referred to as the “setter,” the “downer,” or, in some games, the leader. He or she places the first domino on the table in the center, with its pips facing up. The other players then begin by adding their tiles to the line of play, following the order set out in the rules for that particular game.

As the line of play grows, players must be careful not to knock over the remaining dominoes. If a player cannot play his or her tile, he or she must “knock” the table to signal that a new turn is required. A player who accidentally knocks over a domino must either recall that tile or allow it to stand.

While the rules for each domino game are different, most of them share basic guidelines. The most important factor is to ensure that a domino remains in the correct position on the table before being placed on top of it. This means that all players should be careful to place their tiles in a row and not in a diagonal or triangular pattern.

Another important rule is to never play a domino out of turn. This is called a misplay, and it can ruin the game for everyone. A player who plays out of turn must either recall his or her tile or play it anyway, which is a bad move that can lead to losing points.

In addition to these general rules, there are specific instructions for each domino game. For example, some games require that every player chips out (plays their last tile) before the score is determined, while others use a “chipping out” system where the partners compete to see whose combined total of all spots on their remaining dominoes is the lowest.

Lily Hevesh’s grandparents gave her a classic 28-piece domino set when she was 9 years old, and she fell in love with them immediately. She started posting videos of her creations to YouTube, and now she has more than 2 million subscribers. Watch the video to find out how she uses science—particularly gravity—to create her stunning domino projects.