Take a yo-yo or any other pendulum substitute.

Hold it with your right hand, and put your hand just above your head. Do not swing it; just let it hang.

When you hold it in your right hand, the pendulum will start to softly swing left to right, left to right.

Now hold it the same way, only with your left hand. It will begin to swing to and fro. Towards you, then back, towards you, then back.

Teh magicks.