Roulette’s wheel has a total of 37 pockets, each comes with a number from 0-36 representing pockets. 36 of the pockets were coloured with red or black, and the number 0 coloured with green. In the game of roulette, the dealer spins the wheel in one direction, then spins a ball around a tilted circular track, running around the outer edge of the wheel. Once the ball loses momentum, it should pass through an area of deflectors and eventually drop and stop on one of the pockets, which then determines the winning number and color. 

The ball must complete at least four revolutions around the track of the wheel to constitute a valid spin.