Shoulder workout for those of us who get bored quickly.
First the horizontal position: The Trick here is to think about pushing the floor forward with your hands so that you stay planted against the wall to prevent the feet from slipping down.
The diagonal position: Seems to be the easiest.
The vertical position: Tends to have limited range of motion because your head is in the way.
Wall shuffles: These are great for coordination and actually easier than they look.