In (Ehrenborg & Readdy 1996), a correspondence is given between affine permutations and juggling patterns encoded in a version of siteswap notation. Here, a juggling pattern of period n is a sequence ( a 1 , … … , a n ) of nonnegative integers (with certain restrictions) that captures the behavior of balls thrown by a juggler, where the number a i indicates the length of time the i th throw spends in the air (equivalently, the height of the throw). The number b of balls in the pattern is the average b = a 1 + ⋯ ⋯ + a n n . The Ehrenborg–Readdy correspondence associates to each juggling pattern a = ( a 1 , … … , a n ) of period n the function w a : : Z → → Z defined by w a ( i ) = i + a i − − b , where indices of the sequence a are taken modulo n. Then w a is an affine permutation in S ~ ~ n , and moreover every affine permutation arises from a juggling pattern in this way. Under this bijection, the length of the affine permutation is encoded by a natural statistic in the juggling pattern: ℓ ℓ ( w a ) = ( b − − 1 ) n − − cross ⁡ ⁡ ( a ) , where cross ⁡ ⁡ ( a ) is the number of crossings (up to periodicity) in the arc diagram of a. This allows an elementary proof of the generating function for affine permutations by length.