Roullete is a casino game played on a table marked off with numbers from 1 to 36 and one or two zeros, which offers players a number of betting options. It involves a revolving dishlike device called the roulettewheel into which a ball comes to rest. Bettors may place a bet on a single number, various groupings of numbers, whether they are odd or even, and colors of red or black.

The origins of roulette are murky, though Blaise Pascal is credited with having invented it while working on perpetual motion machines at the end of the 17th century. He apparently used the roulette wheel as a test for his machine, but found that it also had some interesting mathematical properties.

In addition to the symmetry of low red numbers and high black numbers on the two sides of the zero, there is another interesting symmetry in that most of the other numbers fall into pairs with either one odd or one even number. This pair of symmetrical groups is referred to as the second dozen, and bets on it pay 2-1.

A player’s winning bets are kept by the dealer and in the absence of a request they remain up for the next spin, which can make them a good source of extra money. Each player receives six to eight sets of chips, each with a different color, and they have no denomination printed on them (though this is technically incorrect). Each set pays out 300 chips in the event of a win.