• While sitting at your desk, lift your right foot off the floor and make clockwise circles with it.

• Now, while doing this, draw the number "6" in the air with your right hand.

Your foot will change direction and there's nothing you can do about it.

• This time, lift your left foot off the floor and make counter-clockwise circles with it.

• At the same time, draw the number "9" in the air with you left hand.

...thanks to my Uncle Rick for this one