Ed,
This will be a bit hard to explain and nothing outside of class instruction will offer a substitue. This one-man drill was shown to me by three people: 1) Karate instructor who trained with the Machado's for three years; 2) Another purble belt formerly with the Machados who had a shoulder surgery and couldn't practice for awhile but could somewhat do this; and finally someone who studied with Quique (probably screwed that spelling up to).
In any case this is a solo drill for warm-up and movemet and reminds me of breakdancing.
You start with your belly up and arms bent behind you, legs bent, feet touching the floor. You look sort of like a coffee table, doing a crab walk and you are now going to attempt a game of Twister.

Now with this position, you are basically trying to keep your position and move your body and acquire angles.
For instance, lifting up one leg and putting it behind the other leg and then twisting the torso and moving the body around to now face the floor. Similarly, you can move the arms and twist around and do monkey rolls while trying to keep in place.
It's a nice little warm-up drill that has some basic BJJ body movements included.
-B