Shannon’s Juggling Theorem

(F+D)H=(V+D)N

F is the time a ball spends in the air (Flight)

D is the time a ball spends in a hand (Dwell), or equivalently, the time a hand spends with a ball in it

V is the time a hand spends empty (Vacant)

N is the number of balls

H is the number of hands

http://lkozma.net/blog/shannons-juggling-theorem/