A man who collected antiques came to a village one day and found a very old-looking blue bowl on the ground. A cat was drinking milk from it, and its owner, a farmer, sat nearby. Not wanting to reveal his interest in the bowl, the man quietly said to the farmer, "What a nice cat you have! Will you sell it to me?"
"How much will you give me for the cat?" the farmer asked.
"Thirty dollars. Would that be enough?" The farmer agreed. After paying, the man said, "This cat is used to eating from this bowl. May I take the bowl as well?" But the farmer replied, "I'm sorry, I can't give you the bowl. Thanks to this bowl, I have sold thirty cats."