This is a book with the theme of ancient equipment innovation. I hope it can ignite readers' enthusiasm for innovation, actively respond to the national science and technology innovation strategy, and build a national innovation community. A few wooden sticks can defeat the enemy, and a few broken bamboo poles can defeat foreign guns Foreign cannons, and even the legendary hydraulic pestle, hydraulic mill, bed crossbow, trebuchet, wooden ox horse, thousand-mile boat and other ancient top equipment manufacturing. Son, there are three gangs in the world, I am in charge of two and a half gangs...