A foolish man from Zheng wanted to buy a pair of shoes. He measured his feet with a piece of straw by making marks on it. Then, he headed straight for the market. But he was in such a hurry that he left his marked straw at home. So, when he reached the shoe-shop, he said, “I have left the measurement at home and don’t know the size. I’ll fetch it in one minute.” With these words he ran back as fast as he could.
He took the straw and sped up to town. But when he reached the shop, night had already fallen and the shop was closed. The people around went up to him and asked him what had happened. Then they said, “Didn’t you have your feet with you when you were in the shop?” “Yes, of course,” the man answered, “but the straw is very carefully measured, and I am afraid my feet are less trustworthy.”