Sketches for more Shadow Anatomy pieces

Here are some ideas for more on a ' shadow anatomy' theme. I made one piece which was a silhouette made from clay and I showed some organs like the brain and a heart. I don't have a picture right now of it but its in a gallery. I am trying to create some more pieces 'like' that so these are some ideas. I tried drawing with my Wacom tablet, as you can probably tell, which I still feel weird about. It is fun but I definately don't have the same amount of control as over a pen or pencil. Some lack of control can be kind of interesting really and I am not sure how to control the pen sizes yet. How many of you like the tablet drawing tools? I don't use mine a lot so I can't really justify buying a new and more advanced one...