Is it just an inference? Points, lines, surfaces and bodies are zero-dimensional, one-dimensional, two-dimensional and three-dimensional. These phenomena are all related to movement and direction of movement. When a point is fixed or moves with conditions, it becomes a line. If a conditional direction is added to this line (if no direction line or line is added), it is a surface and the surface is infinite. On this plane, both points and lines move with limited time, and then change in the opposite direction to become a body, that is, an object; If conditions are attached, ......