The story of Lu Ban making a chainsaw is about 35 words.

One day, Lu Ban went to a high mountain to look for wood, and suddenly his foot slipped. He quickly reached for a clump of thatch by the roadside. My hand was cut by thatch and blood came out.

"Why is this simple thatch so sharp?" He forgot the pain of the wound, pulled up a thatch and studied it carefully, and found that there were many sharp little teeth on the edge of the grass. He scratched the back of the hand with these small teeth, and actually scratched a hole.

He thought, if I saw the tree with a tool with many small serrations, wouldn't I be able to see the wood soon? That must be much easier than chopping with an axe.

Therefore, Lu Ban asked the blacksmith to make dozens of iron pieces with sharp serrated edges and take them to the mountains for experiments. Sure enough, the tree was soon sawed off.

Lu Ban named this newly invented tool "Saw".