(click to enlarge)
In Photoshop I sketched out some designs, printed them out, then copied them onto the newly cut and sanded wood.
Then with my cheap wood-burning iron I traced the pencil. Unfortunately I only have a chisel tip nib so there was definitely some detail lost (the symbol for "fire of circulation" on the skull for instance) After the wood was burned, a little glue applied, viola! The most practical thing in the world, an eraser box.