This is similar to the triangle in mathematics: the triangle formed by the vertex of the ball and the door frames on both sides 1. The sum of its internal angles is always 180. . If the ball is counted in a straight line when shooting. It is equivalent to the light from the vertex of a triangle, but it is always inside the other two vertices: inside the door frame. In this way, the target point, the door frame and the person's standing point form a triangle 2. In a triangle, the longer its side, the greater its adjacent angle. And when shooting. The closer we get to the target. The more sides of a triangle formed in this way. The longer the opposite side. Then the shooting angle will be larger. . .