An optical illusion is at the top of Reddit this morning, and it's sort of driving the Internet insane.
A user named djeclipz posted the image to the site's r/pics subreddit section Sunday night with the simple caption, "This isn't a gif. Your eyes just can't see all 12 back dots at the same time." From there the online community voted it up until it reached the coveted top spot on Reddit's homepage.
Now I can't stop staring at it, and judging on the number of views on the image (more than two million), neither can a lot of other people.
"It's like playing whack-a-mole with your eyes," is how one redditor described it.
"I'm having an aneurysm," wrote another.
Many of the comments on the image were accusing the poster of major trolling, claiming the image had to be a moving gif, but, go ahead and screen grab it, you'll see that it is indeed a static image.
It's hard to find a reliable answer about what's going on in our brains that's causing the image to look so weird, but one post in another subreddit, r/askscience, offered up this explanation when someone asked "why?"
Because of the surprisingly poor resolution of human vision, and the tricks the brain uses to compensate for it.
You can only see precisely enough to see the black dots at a fairly narrow area near the center of your field of vision, so you can only make them out near where you're currently looking.
Your brain gives you the sense that it's sure the black dots you aren't currently looking at aren't there because of the strength of the grey pattern. It sees that pattern (it's good at seeing patterns) in the area you're currently looking at, sees that the nearby areas (which it has a lower resolution image of) have a similar pattern, and extrapolates. Because most of the intersections of lines don't have black dots, the extrapolated pattern you perceive doesn't include them.
Interestingly, when someone took the original image and lightened the lines in the pattern (below), it changed everything, making it possible to see all 12 dots at once.