A small rectangular block used as a gaming piece. Dominoes are typically made of a hard material such as wood or bone and have one end marked with an arrangement of dots, or “pips,” similar to those on dice. The other end is either blank or identically patterned. The traditional European domino set consists of 28 tiles, also called bones, pieces, rocks, men, or cards, which feature all combinations of spot counts from zero to six.

Most domino games are played by laying dominoes on a flat surface to create a chain of matching ends. The shape of the chain develops as it progresses; when a tile is played to an adjacent double, the two matching ends touch each other fully. This is followed by a subsequent tile being played onto the double, and so on until the entire chain has developed into a snake-line pattern. A domino chain can also be formed by playing several tiles cross-ways over a double, in which case the adjacent pairs of square ends are touching but not adjacent to each other.

Once the domino effect has kicked in, it’s a matter of maintaining the momentum. Jennifer Dukes Lee’s decision to make her bed every day was a small but important step in the larger Domino Effect, which has now led her to establish identity-based habits and maintain cleanliness throughout her home. The same is true for many other behaviors, like drinking a glass of water every hour or removing junk mail from one’s email inbox. The key is to keep making these little changes over time until they begin to shift your identity and become a natural part of your life.

Dominoes have been played with for centuries, and there are numerous variants of the game. Some of the most popular include a variety of blocking and scoring games, such as bergen, matador, chicken foot, and Mexican train. In a blocking game, the object is to empty your hand by placing a domino of the correct value on an opponent’s dominoes to prevent him from playing a tile. In scoring games, such as muggins or bergen, the winning player is the person with the fewest pips in his remaining dominoes.

There are also dominoes made of other materials and with different patterns. Natural stones (such as marble, granite, or soapstone) are sometimes used to add a distinctive look to the sets; other types of hard woods can be used in place of ebony for a more unique appearance and higher cost; and polymer materials can also provide a durable and attractive set.

The word domino has an even earlier sense: it can refer to a long hooded cloak worn with a mask during carnival season or at a masquerade. It also can refer to a garment that covers the head of a Catholic priest over his white surplice. It was later adopted by English speakers to describe the domino effect, which is when small changes have a large impact on an individual or group.