Casinos have been accused of cheating at roulette for years. There are a few ways they can do this, but the most common way is by using a wheel that has been doctored in some way. This can be done with a cloth or paper mask that is placed over the wheel so that the ball cannot hit it. The casino then uses another ball to roulette which has been treated in the same way.
This allows the casino to predict where the original ball will land, and then choose which number to put on the wheel. This method of cheating is not limited to roulette, and is used in many different types of games.
