I love optical illusions because they tell us things about ourselves. And besides that, they’re just plain fun!
I saw this two or three times on FaceBook and that many more times on other people’s blogs and all I could see was a brick wall. Yes, I saw the little gray rock wedged between the bricks. I even learned that was supposed to be the key. It was supposed to be the ash on the end of a cigar. What cigar?
Then I saw it again at the Bad Astronomy site. I know Phil Plait isn’t an idiot. He runs a good blog over there, and I recommend it. If Phil says it’s real, it’s real. But what is there to see but a brick wall and a little gray rock in a crack between two of the bricks. There’s no cigar!
I read his instructions and looked back at the picture. Nothing!
I kept looking. Still nothing.
I looked again. Still nothing.
Then it slowly materialized.
No. There wasn’t any smoke. No mirrors. No visual effects except inside my own head. But the cigar appeared. Now I can’t NOT see it.
Here’s Phil’s explanation:
The illusion is that it’s a cigar stuck in the wall. It’s actually sticking out at a 90° angle, but the shot is taken so that the body of the cigar is aligned with a horizontal gap in the bricks. Together with the cigar being dark, it just looks like the cigar is the gap in the bricks, and the ash at the end is a rock stuck in the gap.
Keep looking. You’ll see it eventually.