A domino is a small, flat block of rigid material used as gaming object. Also referred to as bones, men, or tiles, they are often arranged edge to edge in a line of play and scored based on the total number of exposed ends that match (i.e., one’s touch one’s or two’s touch two’s). In Western dominoes, the word carries the same sense as the game and originally denoted a black domino worn over a white surplice to contrast with the priest’s robe.

When a domino falls, it sets off a chain reaction that can be incredibly complex. A 1983 study by University of British Columbia physicist Lorne Whitehead demonstrated the power of the domino effect: A single domino can knock over something as large as a truck.

Dominoes can be stacked in straight lines, curved lines that form pictures or words when they fall, or 3D structures like towers and pyramids. The possibilities are endless and the resulting patterns can be breathtaking. Dominoes are typically made of polymer, such as a resin, but they can be made of many different materials including woods; metals, such as brass or pewter; ceramic clay; and even glass or crystal.

Unlike playing cards, which have a single identity-bearing face, dominoes are marked with an arrangement of dots on both faces. These dots, called pips, are either the same or different, and are usually arranged in a symmetrical pattern. Most dominoes are colored, though some have a natural, unfinished look. The pips are often inlaid or painted, and the sides of the dominoes are either smooth or textured.

The most commonly played domino games are blocking and scoring. The rules of these games vary from game to game, but they all require a set of dominoes. Most domino games are designed to be played by a group of players, with each player taking turns placing and counting the dominoes in a row or line. The first domino to reach the end of its row wins.

Aside from the most basic games, there are numerous domino variants that offer more advanced strategies and tactics. The most comprehensive book that explains the rules of many of these games is The Great Book of Domino Games by Jennifer A. Kelley, available on Amazon.

Professional domino artist Hevesh has created a YouTube channel where she shows off her intricate creations. Her most elaborate setups can take several nail-biting minutes to fall. She says that the key is using a tiny nudge to get those massive rows of dominoes moving. “When you have the first domino on its tipping point, you can use that little bit of energy to push on the next domino.”