Mo Zhai (Mozi), a scholar from China, and his students made the world's first pinhole inverted image experiment, explained the reasons of pinhole inverted image, and pointed out the essence of linearity of light. This is the first scientific explanation for the straight-line propagation of light. In the Book of Mo, it is recorded that pinhole imaging is like this: "When the scene arrives, it will end in the afternoon, and it will grow with the scene. Let's talk about it at last. "