As someone whose icon is an optical illusion, I should weigh in on the photo that's been making the rounds in the last few hours (so everybody knows about it already, you out-of-touch hick) of a dress that some people see as blue and black (reportedly the actual colors) and some as white and gold. Here's an article about it with a copy of the original photo framed by versions with the color balance changed in either direction.
And which do I see? Both.
When I first looked at the photos this morning, I saw white and gold. No blue whatever, except perhaps the faintest touch of it only in the horizontal ribbing. The central picture was almost identical with the left one, only of slightly darker hue - what you'd call shaded white.
I looked at it again an hour later and it had turned blue. A far paler blue than in the right one, but definitely blue. The gold, though now darker and tarnished, was, however, still gold. No black, sorry.
It really looked like they'd switched the photos. Fascinating. We've always been at war with Eastasia.
ETA: Now even the left-hand white image looks faintly blue.