Creepy disembodied extremeties

I've had the very good fortune to get to know a talented and well known medical illustrator around here. I've talked to him about my plans and gotten some very good advice. From our first conversation he's been curious about my past and ongoing fine art training, reminding me that no matter how many cool tricks I can pull off in Illustrator, it is important to stay strong in the fundamentals. When I told him we had to draw our hand in class, he told me we should have been drawing our hands and feet about 20 times, using different types of pencils, methods of shading, and lengths of time. So, here are some of my attempts. The sketches took anywhere from 5 minutes to an hour. They were done with charcoal or pencils at 6 or softer. Some are blended, some are not. 8 down, 12 to go. Or is it 32 to go? The topmost sketch is the one I did today. The foot in the last panel is not bleeding, it's just a smudge.