I am really fascinated by making these sort of shapes. I think I first saw something like this done by Saul Steinberg from back in the 50's.
It is a sort of abstract construction, random shapes that looks like something solid but don't really add up to anything specific... I call them Scraps. Anyway, I had fun shading and colouring it and thought I should do more of these, maybe even try and make a little sculpture or some repeating patterns.