Bob liked collecting vases (花瓶). He had a vase from China. He liked the color very much and decided to have the wall of his bedroom painted the same color as the vase. He then asked many painters to paint the wall. But none of them could make it.    
    One day a young painter came. He told Bob, “I can paint your wall.”
    “OK, but you must pay 50 dollars for this chance. If you fail, the money will be mine,” said Bob.
    “No problem! But I have a habit of working alone. Come to see your wall in four hours, please.” said the painter.
    Several hours later, the painter came out and told Bob, “Please come in.”
    “Congratulations!” Bob said. From then on, the painter became famous.
    When the painter was too old to work, he taught his son all his skills. “But father, there’s one thing I don’t understand. How did you finish Bob’s task many years ago?”
    “Well, it’s easy. After I painted the wall, I painted the vase with the same color.”