Flutterby™! :

In the "doh, why didn't I think of that" department, here's an awesome patent (If you go, be sure to read the full descriptiong) for a "Photon push-pull radiation detector for use in chromatically selective cat flap control and 1000 megaton earth orbital peace-keeping bomb".

But if light comes in indivisible "photons", as shown in Figure 2(A), ifyou are one such photon, how do you decide whether to go on through, or bounce back, or reflect or, in other words, "Does God play Dice with the Universe?" I am informed by a Professor of Physics that there is "no one on Earth", who can explain this simple problem for me.