The vertical conveyor on the right side brings both pins and balls up from the lower level into the mechanism. You can see at some point that the balls, since they are of a smaller diameter than the pins overall, will fall through a mid-height channel to travel down the chute back to the bowler. The wider diameter pins travel to the top of the vertical conveyor in order to be set in a line to drop into the pin cups that rotate around a serpentine path on a chain in order to place them in the proper spots for pickup by the pin tray when it is time for their turn to be set in place on the lane floor. The red pin cup that I pointed to at the end is the "last", or in this case, the 10th pin to be set in the cup train, and if the system is mis-aligned such that the last pin is not in the red cup, the system will not function properly.
