This is related to the surface of the mirror. When we face the mirror, if it is concave, it will be thin, if it is convex, it will be fat. Of course, the surface of the mirror is very small and not easy to detect. The bigger the mirror, the smaller the curved surface, which makes the fat and thin effect obvious; On the other hand, if the mirror is small, it is difficult to detect the effect of being fat and thin. I hope I am satisfied! !