"The following requirements are mandatory for Levels 2 4 both in Short Program and in Free Skating: a) for Spin Combinations with change of foot all 3 basic positions; b) for Spins with change of foot at least one basic position on each foot." I *think* I know what part a) means, but unsure about part b). Clarification on both would be great. I'm trying to watch competitions and know more about what I'm watching. Thanks!