Attached is a very elementary paint illustration of how this works (if I understand it right), for those of you having trouble understanding.
The balls rest in such a position that most of them are slightly influenced towards the center of the rack. This gives it some tolerance for different sized sets of balls as well.
The balls rest in such a position that most of them are slightly influenced towards the center of the rack. This gives it some tolerance for different sized sets of balls as well.