Sent this to an engineer friend of mine, his response is below...
It's called a priority interrupt. The tiny, pea sized microcontroller we have as brains, tells the foot to move in a clockwise direction. At the same time, the hand is drawing the number six in the air. On the backstroke to complete the six, the microcontroller gets an interrupt to change directions, so you foot moves in the opposite direction. I tried it with my left foot and ended up sucking coffee up my nose. Now I have to go outside and take a ****.
Thanks for screwing up a perfectly lousy Monday.