Who is the hero who teaches fish to swim?

Ruban. Once upon a time, there was a man named Lu Ban, who was famous for his dexterity and was regarded as the father of craftsmen. Experts admire him with admiration. One day, a young carpenter casually walked to a house in Dahongmen, raised his axe and said, "I don't care about this axe, but no matter what wood it is, as long as I get it in my hand and use my axe to do it, I can make beautiful things." Hearing this, the people next to him felt that he was too boastful and pointed to the Dahongmen behind him and said, "Ultrafine products, can you make a better door than this?" The young carpenter said proudly, "I'm not bragging." I tell you, I used to be a student of Luban. Can't I make such a simple door? It's a joke. " Everyone couldn't help laughing and said, "This is Mr. Luban's home. He made this door. Can you really make a better door than this? " The young carpenter ran away shyly. Showing off one's skills in front of experts.