First, rhinoceros horns grow on the nose, with single horns and double horns. Because it grows in the middle of the head, it is closer to a circle or a large ellipse; The horns grow on the forehead and diverge to both sides. Because the cow's forehead is flat, its horns are flat.
Second, all angles have a * * * property, that is, "the former is real and the latter is empty", and "the former is real where the angle refers; Back space "means that the place pointing to the nose or forehead is concave." The older the cow, the longer the hollow and the shorter the solid.