A famous art collector is walking through the city when he notices a mangy cat lapping milk from a saucer in the doorway of a shop and he does a double take. He recognises that the saucer is extremely old and very valuable, so he walks casually into the store and offers to buy the cat for a couple of quid. The storeowner replies “I’m sorry, but the cat isn’t for sale. The collector says, “Please, I need a hungry cat around the house to catch mice. I’ll pay you twenty quid for that cat.” And the owner says “Sold,” and hands over the cat. The collector continues, “Hey, for the twenty quid I wonder if you could throw in that old saucer. The cat’s used to it and it’ll save me from having to get a dish.” The owner says, “Sorry mate, but that’s my lucky saucer. So far this week I’ve sold sixty-eight cats.”