Rotation 90 degrees CLOCKWISE
(X,Y) will turn into (Y, -X)
Rotation 90 degrees COUNTERCLOCKWISE
(X,Y) will turn into (-Y, X)
Rotation 180 degrees
(X,Y) will turn into (-X,-Y)
Reflection over the Y-axis
(X,Y) will turn into (X,-Y)
Reflection over the X-axis
(X,Y) will turn into (-X,Y)