Older pachinko machines had a spring-loaded lever for shooting the balls individually, but newer ones use a round knob that controls the strength of an electrically fired plunger that shoots the balls onto the playing field. When shot, the balls drop through an array of pins; some of them will fall into the centre gate and start up the slot machine in the centre screen. Every ball that goes into the centre gate results in one spin of the slot machine, but there is a limit on the number of spins at one time because of the possibility of balls passing through the centre gate while a spin is still in progress. Each spin pays out a small number of balls, but the objective is to hit the jackpot. The program of the digital slot machine decides the outcome of the spin when the ball falls through the center gate, not when the spinning animation plays.