Dominoes are a timeless toy that can be used to make straight lines, curved lines, grids that form pictures when they fall, or even 3D structures like towers and pyramids. The physics behind the domino effect is interesting to observe, as potential energy converts to kinetic energy and is transferred from one domino to the next until the entire line falls. This is also a great way to teach kids about gravity and momentum, since the entire process is easy enough for them to understand.

Dominoes (also called bones, cards, men or tiles) are rectangular pieces with a number written on each end in either dots or Arabic numerals. The digits on each end indicate the value of the tile, with values typically ranging from six to zero or blank. The more digits on the domino, the higher its rank or value. Each player must in turn place a domino on the table, positioning it so that one of its ends touches an open end of another domino. Normally, a domino must be placed squarely in the chain, although doubles are sometimes played cross-ways instead of straddling the long side of the adjacent tile. If a domino has no matching end, it is said to be an open end and any additional dominoes may be placed against it at their discretion.

There are many games that can be played with a domino set, but the basic rules all center around blocking and scoring. The first player to play a domino, determined by drawing lots or the owner of the heaviest hand, starts the game. A player can only place a domino so that its end touches an open end of another tile, and only if the resulting chain has sufficient length to advance the game.

The simplest domino sets are made of plastic or polymer, with black or white pips inlaid or painted on the surface. More luxurious sets are available in materials such as bone, silver lip ocean pearl oyster shell (mother of pearl), ivory, and dark hardwoods such as ebony. These natural-material sets have a more elegant look, but they are significantly more expensive than their synthetic-material counterparts.

A popular variation on the domino game involves arranging and then destroying a complex structure of interconnected dominoes. This is often referred to as domino art, and it can be used for display or for the purposes of entertaining guests. The art can be as simple or elaborate as desired – it is a form of sculpture that allows the artist to use his or her imagination. It can be a great activity for children to do on their own or with friends.