Roullete is a casino game in which a ball is spun around a revolving wheel and bets are placed on the number or combination of numbers into which it will come to rest. Bets are made by laying chips on a betting mat, the precise location of each chip indicating the bet being made. Each bet pays off at different odds, depending on whether it wins or loses. Bets placed on six numbers or less are known as “Inside bets” and those on more than 12 are called “Outside bets”.
There is a variety of theories about the origin of roulette, including that it was invented in the 17th century by Blaise Pascal, a French mathematician, philosopher and inventor who was trying to create a perpetual motion machine. It became popular in Europe during the 18th century and spread to the American colonies where it gained widespread popularity. It is now played in casinos and gambling dens throughout the world.
The roulette wheel consists of a solid, slightly convex disk divided by metal partitions or frets which are painted alternately red and black. There is also a green compartment, numbered 0, and on some American wheels there are two additional green compartments numbered 00. These are referred to as the double zeros and they are what make the American version of the game a worse proposition financially than the European version.
In addition to the symmetries of the green numbers there are some other interesting symmetries in the wheel. In particular, the low red numbers and the high black numbers are grouped together on one side of the wheel while the other grouping contains no numbers from 13 to 24 (the second dozen). This means that it is possible to place a bet on the corresponding section of the wheel with odds of 2-1.
The ball used in roulette is normally made of ivory although nowadays it is more likely to be a Teflon or resin type material. The difference in size and weight between a real piece of ivory and a modern, lighter ball makes a noticeable impact on the way the ball bounces around the wheel track before it finally comes to rest. This is why some gamblers believe that the casinos should allow players to choose their own balls before each spin of the wheel.