According to historical research, the creatures on the earth were ruled by turtles tens of billions of years ago. At that time, the characteristics of turtles were very different from those of turtles today, that is, the head was bigger than it is now, and it never shrank into the shell. Why did the tortoise start to shrink back after evolution? It turned out that there was a famous writer in the turtle culture at that time. He wrote a famous book called How not to offend turtles. In the book, Xiao Zhi expounds the truth of being a turtle emotionally, and uses a lot of examples, that is, never offend the same kind, step back at the critical moment and put your head in the shell, so that you won't curse yourself and be assassinated by the villains.