If A (X,y) is a point in the in the orthogonal Cartesian coordinates system of two dimensions and "O" is the origin point , then :
1.A (X,y) ----------------> By Rotation R (O , 90° & -270° ) A' (-y , X )
2.A (X,y) ----------------> By Rotation R (O , 270° & -90° ) A' (y , -X )
3.A (X,y) ----------------> By Rotation R (O , 180° & -180° ) A' (-X,-y)
4,A (X,y) ----------------> By Rotation R (O , 360° & -360° ) A' ( X , y)= A
