A little three year old lad is sitting on the loo. His mother thinking he has been in there far too long, so she goes to see what he's up to. There he is, sitting on the toilet reading a book but every fifteen seconds or so, he puts the book down, grips onto the toliet seat with his left hand and hits himself on the top of the head with his right hand. His mum says, "Danny, are you alright, you have been in here ages?" Little Danny replies, "I'm fine mummy. I just haven't gone potty yet." Mum says, "OK, Danny, you can stay here a few more minutes but why are you hitting youreslf on the head for?" Danny says, "Well it works for ketchup."