I made a grinder! It's doesn't grind all the way down to nothing, it just messes up things inside it. Three pairs of gears, with the middle pair rotating counter to the two outer pairs. It's powered by a pull-rod, kind of like starting a lawnmower. As you can tell, it's designed to grind something about the size and shape of a bratwurst, causing horrific damage but not actually destroying it. Obviously I had to use gears because I have no lego teeth.