One day a visitor came to Nasreddin's house. "I am your cousin from Konya," he said, "and I have brought you a duck to celebrate the visit." Nasreddin was delighted. He asked his wife to cook the duck, and served the visitor a fine dinner.
The next day another visitor arrived. "I am the friend of the man who brought you the duck," he said. Nasreddin invited him in and gave him a good meal. The next day another visitor arrived, and said he was the friend of the friend of the man who had brought the duck. Again Nasreddin invited him in for a meal. However, he was getting annoyed. Visitors seemed to be using his house as a restaurant.
Then another visitor came, and said he was the friend of the friend of the friend of the man who had brought the duck. Nasreddin invited him to eat dinner with him. His wife brought some soup to the table and the visitor tasted it. "What kind of soup is this?" asked the visitor. "It tastes just like warm water." "Ah!" said Nasreddin, "That is the soup of the soup of the soup of the duck."