Hold up 3 balls and only 1 ball at a time in your hand.
Hold up 4 balls and you are only allowed to hold up 1 ball at a time.
In total 3 balls, where 1 ball is thrown in between and both have 1 ‘own’ ball. Before you catch the thrown ball, you throw your 'own' ball up, catch the thrown ball, throw it back and catch your 'own' ball. And so on.
Play 1 ball overhead, 1 ball bounce on the ground.
Play 1 ball overhand, 1 ball over ground.
Play 1 ball overhand, 1 ball roll with arms stretched over ground.