《天工开物·下篇·佳兵》
山区的居民用来射杀猛兽的弩叫做 窝弩 ，装在野兽出没的地方，拉上引线，野兽走过时一触动引线，箭就会自动射出。
其山人射猛兽者名曰窝弩，安顿交迹之衢，机傍引线，俟兽过，带发而射之。
The crossbow used by residents in the mountainous areas to shoot fierce beasts was called the "wo crossbow", placed in places where beasts appeared, armed with a wire, when the beast passed by and triggered the wire, the arrow would shoot out automatically.