This was something I first observed while being an artist in residence at the Kohler Co. in Wisconsin in 1986. Watching the foundry men cut gates and vents in the bonded sand, it became clear how this was a spontaneous process which circumvented much of the laborious steps in casting metal. It is a wonderful niche between drawing, wall relief and sculpture. I enjoy those overlaps. It's durable and can work outdoors. I have installed these in several situations, such as fences, gates and outdoor art. When you work this way, you have to turn your head around like a mirror because you must carve the image in reverse. This is actually a very useful habit to have as an artist.