Siteswap notation is different for synchronous juggling: Throws are given in pairs (x,y) with left hand throwing x and right hand throwing y at the same time. There is an implicit brake after each pair, so only even numbered throws are used. A star at the end of the pattern denotes that the throws are repeated with left and right hands reversed. The throws are: 0 Hand is (and stays) empty. 2 Ball is held in the hand. 2x Quick pass to the other hand. 4 Normal throw to the same hand. 4x Relatively high throw to the other hand.
Step 1 When juggling two balls in the same hand, throw a third ball synchronized with one of the other balls.
Step 2 Concentrate on the ball that is thrown alone, and throw it to the other hand every once in a while.
Step 3 Swap hands each time.
Variant Include some outside throws to get columns.