The butterfly is one of the first elementary moves in contact juggling. Deriving from the windshield wiper, it is a beautiful move that can greatly aid in advancing the juggler's ability in one-ball technique.
The butterfly is achieved by balancing a ball on your palm, arm out, then flipping your hand over in a arch and catching the ball in a cradle position, and vice versa. The move is very similar to the windshield wiper; however, in the butterfly, your elbow and the arch made by your hand and the ball becomes looser than portrayed in the windshield wiper; you should end up with the ball moving back and forth in a figure eight pattern. Be sure to practice your figure eight pattern in both directions, with both hands.