This optical illusion bamboozled over 3 million people

A couple of years ago an optical illusion came along and almost broke our site. Over three million people read an article about the most dizzying illusion ever to grace our screens – the rotating horse. And all this time later, I still can't work out which way it is turning.

The horse spins and spins but seems to keep changing direction, and making my head spin in the process. I delve into why that happens further down the page, but first check out one of the top optical illusions ever ad see what you think.

Blinking doesn't help to settle things, nor does moving further back from the screen or looking at the illusion sideways – or any of the other tricks people suggest to help make sense of optical illusions.

So why does this happen?

According to WhatPsychologyIs,"due to the image’s lack of visual cues for depth, the ambiguous 2-dimensional figure can be seen from two different perspectives. This alternation between two perceptual states is referred to as bistable perception."

The gif was originally posted on a TikTok account that doesn't exist anymore, but the horse reigns on as one of the most confusing things we've ever reported on. Recently we found this spinning ballerina that does a very similar trick – and comments on this illusion offer advice on making the ballerina change direction. Unlike the rotating horse, the ballerina only spins one way for me – does it for you?

Which Way Is She Spinning? from r/opticalillusions

For even more head-spinning illusions, see this super-arty Van Gogh illusion that also made us dizzy. This one works in a very different way – and is full of colour, where these are boringly black and white.