What are single perspective, double perspective and triple perspective? Please explain it in simple language. Baidu's explanation is very complicated. And three perspective views are given.

Point perspective (also called Parallel perspective): It is the perspective of a square or rectangular object with one side parallel to the picture. This perspective has a sense of neatness, flatness, stability and solemnity.

Two-point perspective (also called angular perspective): it is a perspective in which the side of an object and a parallel square are not rectangular. This perspective can make the composition more changeable.

Three-point perspective (also called oblique perspective): that is, when the face and edge line of the cube are not parallel to the picture, the edge line of the face can be extended to three vanishing points, overlooking the plane.