Multiplex Siteswap
Multiplex throws in Siteswaps are written in square brackets and mean that the numbers inside the square bracket are several ball thrown at the heights as indicated by the numbers.
For example, [45] means two balls are thrown at the same time, one takes 4 beats and the other takes 5 beats until they are thrown again.
The same rules as for vanilla siteswap apply - except that now two objects have to land on the site thrown later as a multiplex.
Because squeeze-catches (catching two different throws at the same time) are hard to do, for practical purposes most often one of the throws is a siteswap for which the throw can be skipped (i.e. a "2" for two hands).
Like for example
Here 2 and 1 both end on the same beat and in the same hand. The "2" is just held after the throw, the second ball is zipped into that hand.
For swapping sites with the multiplex site, you swap sites with *one* of the two numbers in brackets. So for example from [45]21 you could swap 2 to the left with 4 and would get [35]31 (→ see animated gif on jugglinglab.org).
Again, for practical real-world juggling purposes, you can only end up on multiplexes inside the bracket that you have actually learned how to throw. And by now collecting the two balls needed for the multiplex throw by simultaneously catching a "3" (self) and a "1" (zip), we made collecting quite a bit harder.
