You may have seen this dress from tumblr:

It’s meant to be black and blue, or white and gold. Some can see it both ways and some see it differently after going for a walk.

I think it’s blue and gold – definitely!

For different reactions, see Business Insider.

I’ve heard two different academics explain what’s going on. I’d say that colour comes to us through light waves, but is constructed subjectively by each of our brains.

I think the clue on this one is that they used blue and black and ran a yellow light filter over it.

From Mark’s Facebook here are a couple of pics riffing off the original:

By the way, we used to have a carpet at our place until we ripped it up. I saw it as grey, my wife saw it as green. She was right, of course!