A domino is a small rectangular wooden or plastic block with a flat top and one or more sides marked by an arrangement of spots resembling those on dice. Dominoes are usually twice as long as they are wide, making them easier to re-stack when playing games. The spots are called “pips” and the dominoes are often described as being either “heavy” or “light” depending on how many pips they have. The heaviest dominoes have six pips, while the lightest are blank or only have three pips.

The blocks are stacked on end in long lines, and when one is knocked over it causes the next domino in line to tip over, creating a chain reaction. This is the domino effect, and it allows people to create very intricate designs with the dominoes.

In addition to being used for artistic and decorative purposes, dominoes are also often used in games of chance and strategy. They are played by two or more players and are a great way to pass the time and have fun with family and friends. In some cases, dominoes are even used to help teach children basic math and counting skills.

Some games are designed to be played by only one person, while others involve more than one player and may include scoring elements. Generally, the more dominoes that are used in a game, the more exciting and complex the play can become.

The most common domino games are blocking and scoring, with the latter normally involving a game of fives and threes, in which points are scored when one or more of the dominoes has a sum divisible by either of these numbers. Dominoes are sometimes used for a variety of other games, including solitaire and trick-taking, which were commonly used to circumvent religious proscriptions against the use of cards.

Dominoes can be arranged in a wide variety of patterns and can be played with almost any kind of table, although some are more suitable than others for different games. A large surface is often required for very complicated games, while smaller ones can be played on a table or floor.

A key factor in the creation of a domino chain is how the individual tiles are positioned on the table. Each tile must be positioned so that its matching ends are touching. The ends are sometimes referred to as being “open” or “closed” depending on whether a tile can be added to the chain on its short or long side. When a double is used, additional tiles can only be placed to the right or left of it but not diagonally across it.

When a domino is pushed down, it has inertia, which makes it resist motion until enough force is applied to overcome it. A tiny nudge is all that is needed to tip a domino past its point of inertia and start the chain reaction. Hevesh spends a lot of time testing out her creations before they are filmed so she can make sure they will work as planned. She has worked on projects involving hundreds of thousands of dominoes, and her largest installations can take several nail-biting minutes to fall.