Another Aussie! Welcome to the Cellar, RodinPat.
We're getting a formidable contingent from down under....that's great.
tulzscha, you may be right. The IOtD picture could be picking up some color from the window combined with the photographic technique. I was just pointing out the other oil slicks we've seen in the news, and in person, show color, so it can't be the total cause.
The effect shown in the website you linked is an extreme case and exactly what we do in the lab to show strain. Attaching Plexiglas to a part and subjecting the part to stress, the strain will show up in the Plexiglas clearly enough to photograph it.