Skulls... I like printing X-Rays on transparencies & putting a light behind them. I generally use a very thin white paper behind or around them for a more finished look. I've yet to do a lampshade with them... but it's on the list.
fra Scientific Illustration
12 Year Old Skull
Google Image Result - Never more..
Trio of skulls
50 Cool Skull Tattoos Designs
Freehand skull on head tattoo Cráneo a mano alzada en cabeza del tatuaje