It is from an orthopaedic surgeon............ This will boggle your mind and you will keep you trying over and over again to see if you can outsmart your foot, but, you can't.  It's pre-programmed in your brain!
  
1. While sitting at your desk in front of your computer, lift your right foot off the floor and make clockwise circles.
  
2. Now, while doing this, draw the number '6' in the air with your right hand. Your foot will change direction.

Can ya do it?