OK, try this......
sit in a chair, put your right leg straight out in front of you and move it in a clockwise circle. Now, try to draw the number 6 in the air with your right finger.
Can you do both at the same time???
It's hard!
Jeff showed me this--I was able to do it after a couple of tries, but with a lot of concentration!!
Neither Jeff nor the kids could do it--it drives you crazy!!