Drawing on something other than fabric or paper

I have used permanent marker to draw on a metal tray my mum was gonna chuck out. The metal is all crumpled because my cousin thought it would be funny to punch it when I put it on my bed, but I wasn't so annoyed because I like the effect that has been created. I just drew a simple image of a man. It was quite hardly to draw on because of the metal but being straight or flat but I love the effect created when the light reflects off the metal and the permanent marker.