Haddon Robinson, Biblical Preaching, p. 102
A Chinese boy who wanted to learn about jade went to study with a talented old teacher. This gentleman put a piece of the stone into the youth's hand and told him to hold it tight. Then he began to talk of philosophy, men, women, the sun, and almost everything under it. After an hour he took back the stone and sent the boy home. The procedure was repeated for weeks. The boy became frustrated&md;when would he be told about jade?&md;but he was too polite to interrupt his venerable teacher.
Then one day when the old man put a stone into his hands, the boy cried out instantly, "That's not jade!"