Introduction to the magical stone: About 500 meters up the Tanggu River from the mouth of Tanggu, there are two huge stones standing on top of each other, each weighing 200 tons. On a stone above, the words "Shen Gong" written by Li Zhi, Emperor Gaozong of the Tang Dynasty, still exist today. Its mystery is that it doesn't move at all when everyone pushes it, but if you find the fulcrum of force and one person only exerts a little force, it will slowly shake.