what’s the frequency kenneth?

Tom Stafford of Mind Hacks has a quite good explanation of what’s known as the spatial frequency effect, a heuristic tool for gauging visual perception.
The gradient of stimuli is measured against the contrast between light and dark and the angle, the point of view. As an illusion or illustration that creates itself, the phenomenon might be best imparted as the trick that superimposes a couple of iconic images of Albert Einstein and Marilyn Monroe whose hybrid, composite picture shifts from one to another depending on the viewer’s distance.  Lean forward, lean back to experience it to the fullest.  I wonder how this interaction between the seer and the seen might be manifested in other ways.