My son is 4 years old and goes to our local play group of a Thursday. The other day he was sitting in a corner with a wooden block and a play dough knife stroking it back and forward. One of the mum's asked what he was doing and he told them with out looking up that he was shaving. My wife just shook her head.

I don't know how long he was at it for but I reckon it'd take a while to get an edge on a plastic knife with wood, but you never know it may have passed the HPDS (hanging play dough snake) test