I did this as a joke once. (I wish I had a photo to post)
I was working in the airforce and this guy cut open his hand with a scalpel blade. So one guy lay down and I traced around him with a pencil, then laid down a ‘chalk’ (actually it was masking tape) outline.
I added the outline of the scalpel blade, and we left some of the blood on the floor (next to the blade). I had to clean up the rest though. :-)
Was a good laugh when he got back to work that afternoon. I think the outline stayed there until I got posted away.

