The Slot Machine Anatomy. A certain number of reels, usually three or five, are decorated with different symbols in each slot machine. Players try to line up these symbols in particular ways swhat is yonoo they can get paid. Bonus features & payout arrangements. Games differ in their payout structures; some machines have fixed jackpots, while others have progressive jackpots that increase in value as more players play. Also, a lot of contemporary slots include bonus features like scatter, wild, and free spins, which can greatly improve the playing experience and raise winning odds.