“ Lu Ban was a famous carpenter in the Chun Qiu period. One day he went up the mountain to chop wood. He wasn’t careful going up the mountain and slipped, grabbing at some grass to stop his fall. The grass cut his hand. He looked carefully at the grass and noticed that it had teeth along its edge. He thought, if I made a tool with an edge like this grass it certainly would be very sharp and could cut wood. Based on this idea, Lu Ban invented the saw. With a saw, a carpenter can cut wood very easily.
