Leaf carving involves cutting away at a leaf until it reveals an image. This is a craft practiced by Nature's Art, a studio in Hengshui, China. At the link, you can view several other examples as well as instructions on how to make your own.
http://www.longal-craft.com/leaf-carving-art.html via Make | Photo: Nature's Art
In which case, it is really cool.
1) Find scrap metal.
2) Clean scrap metal.
3) Dry scrap metal.
4) Sort scrap metal.
5) Build car.
Seriously: it looks nice and all, but it's not carving; it's painting.