Using the same didactic style as the author, I would like to show how it is possible to replace the image rotation algorithm with a NOOP. First, look at any of the pictures shown. Next, turn your head to the side 90 degrees. Although the computer's output hasn't chamged, by redefining requirements we can achieve the the desired change. The fastest way to rotate a square is a noop (or O(1) message to the user): turning your head. Never forget it!