We're not sure whether this can be categorised as an optical illusion or if it's simply a perfectly timed photo but it's been driving the internet nuts.
Which is impressive, actually, considering how boring the subject is.
A picture uploaded by a model called Rose has gone viral after social media just could not figure out what the hell was happening to her legs.
We're not going to spoil anything so have a look at the original first.
Basically it's your run-of-the-mill mirror selfie, purporting to show off how Rose "just combined vertical and horizontal stripes."
So far, so boring. But have another look at her lower half. Are you seeing two legs, or one leg? Because that's just one leg
That "gap" in between her legs is actually a stripe down the middle of her trouser leg, perfectly matching the colour of the wall and floor behind her.
We didn't say it was going to be satisfying.