A number of programs are available that
simulate site swaps on a computer screen, sometimes with quite
impressive graphics. These programs take a finite
sequence of non-negative integers as input and dynamically represent the
The Internet news group rec.juggling is a source of information
on site swaps and various juggling animation software.
In order to find out which finite sequences represent juggling
patterns we start by noting that a period-n pattern induces
a permutation on the first n integers.