A very characteristic toy object of the Real World
Jacks are a component of an ancient bet-chance game played by humanity. These are usually made of different materials, the most common being plastic and metal, which are usually used by toys as obstacles for vehicles (especially metal ones, due to their heaviness which makes them difficult to move).
Knucklebones game
The game “knucklebones” is the name given to different children’s games and games of chance played by humans that consist of throwing some bones (or tabs) as it says. These were replaced over time using the jacks obstacle objects.
The “knucklebones” (scientific name astragalus) is a bone found in the tarsus of a large part of carbon living beings, especially mammals. Since ancient times, humans have used the paws of some animals, particularly those on the hind legs of lambs (about 3 × 2 cm), to play different games, some of which were children’s but others were games of chance played by adults. They are all based on throwing the knucklebone like a dice on the ground or on a table, with the particularity that, unlike the dice, the different faces of the knucklebone have different shapes and therefore different probability of coming out. In some of these games, bets were placed (sometimes large amounts of money) on which side of the table could be visible (up). The simplest game consists of throwing the knucklebones, winning one or four units bet if the protruding parts of the bone remain downwards, or losing the same number if the parts remain sunken on the upper face.
The game of knucklebones was introduced by the colonist Spanish humans throughout America and was very popular in rural and livestock areas where there was access to cattle bones.
Sometimes, the knucklebones were modified by polishing some of their faces and adding a veneer to make the face smoother and flatter. During the 20th century in some regions or countries the game was so popular and the demand for these bones was such that the currently used “jacks” were made of plastic, resin or metal.