I also see lots of problems with this. The major one being that there is nothing to hold the rock against while you hit it with the long nail. Nail hits rock, rock hits badder. Then you have all these smaller pieces and you're going to just go stabbing around randomly trying to break them all up into even smaller ones?
I've heard of old dudes having a long straw of grass in their hat that they would use to thread up in there and push the rock aside when they had to pee. Each and every time.
