Dominoes are small rectangular blocks of wood or plastic, with a blank or patterned face on one side and an arrangement of spots, resembling those on dice, on the other. They are normally twice as long as wide, although there are some exceptions. The pips on a domino are sometimes called its rank or value, but they may also be referred to as numbers, spots, digits, or dots. The number of pips on a domino, as well as its color and shape, determines its rank and weight in games played with it. A domino with more pips is a “heavier” or “more valuable” than a domino with fewer pips.

There are many different games that can be played with dominoes, each requiring a different strategy. The most common are blocking and scoring games, where players try to empty their opponents’ hands or block them from playing their tiles. The player who scores the most points in a given number of rounds wins. The earliest known domino game was invented in China around the 17th century to circumvent religious restrictions on the use of cards.

In addition to being fun to play, domino can teach lessons about time management and goal setting. One way to achieve a large task is to break it down into smaller, manageable parts, and to focus on the most important task first. This is known as the domino principle, and it was a key factor in the success of steel magnate Edgar Allen Lee’s business, Bethlehem Steel. Lee told his employees to always start with the biggest or most important task of the day and work toward its completion before moving on to other tasks. He called this the domino principle because completing that task would have the most impact on the company, and it should receive full attention until completed.

The term domino also has a more figurative meaning, suggesting that an event or result will cascade into other events in a predictable fashion. The word is used in a wide variety of contexts, from business and politics to social interaction and even as a form of art.

Physicist Stephen Morris believes that the physical phenomenon that allows dominoes to create intricate arrangements is gravity. When a domino is stood upright, it stores energy, giving it potential power. When it falls over, that energy is converted to kinetic energy, causing it to push the next domino over and create a chain reaction. The larger the setup, the more dominoes are needed to topple.

A domino set usually consists of 28 dominoes, although extended sets can contain more than double that number. These progressively larger sets add new ends with increased numbers of pips, which increases the possible combinations of values for the tiles. A domino with a value of six on both ends is a double-six, while one with four on both ends is a double-four.