Nasreddin and the pot
One day Nasreddin borrowed a pot from his neighbour Ali. The next day he brought it back with another little pot inside. "That's not mine," said Ali. "Yes, it is," said Nasreddin. "While your pot was staying with me, it had a baby."
Some time later Nasreddin asked Ali to lend him a pot again. Ali agreed, hoping that he would once again receive two pots in return. However, days passed and Nasreddin had still not returned the pot. Finally Ali lost patience and went to demand his property. "I am sorry," said Nasreddin. "I can't give you back your pot, since it has died." "Died!" screamed Ali, "how can a pot die?" "Well," said Nasreddin, "you believed me when I told you that your pot had had a baby."