If you stay inside the vanilla restriction, you´ll get 4 handed siteswaps with hands throwing alternately. This means, a 4 handed ‘global’ siteswap sequence gives you the throws for right hand juggler 1, right hand juggler 2, left hand juggler 1, left hand juggler 2 and again. So, juggler 2 starts half a beat after juggler 1 and they never throw at the same time.
Additionally, one of the jugglers throws straight passes while the other throws crossing passes.
4 handed siteswaps are incredible to discover new passing patterns as they combine different selves with different passes. For the passes, it is important that they alternate between straight and cross with height. For example, if juggler 1 chooses to throw straight single passes, he will cross both his zaps and his double passes. Juggler 2 will then throw straight zaps and double passes and crossing single passes.
4 handed sitswaps of odd period will change from right to left hand (symmetric patterns) same as odd period 2 handed siteswaps.
Different 4 handed siteswaps are compatible, meaning that juggler 1 can do a different pattern than juggler 2 – that´s especially great for juggling groups of mixed skills – better jugglers can pass a difficult pattern against an easy one.
Christian Kästner compiled an online, searchable list of compatible 4 handed siteswaps.
In this list, the numbers mean:
2 = zip (very fast self without spin)
4 = hold or flip
5 = zap (fast, half-spun pass)
6 = single self
7 = single pass
8 = heff (double spun column self)
9 = double pass
a = 10 = triple self