What started innocuously at the beginning of the week as nothing more than a quirky point-of-view snap of an Instagram user’s legs has quickly escalated into an internet sensation on a scale not seen since the hotly contested colour of "that dress" in 2015 made the world want to tear its eyes out. At issue in the current hullabaloo is whether we initially perceive an unusual slickness to the skin, as if the legs had been oiled, or whether we see merely a few streaks of white paint smudged on her bare outstretched pins.
In the 48 hours since the photo of Hunter Culverhouse's legs was re-posted on Wednesday by a mischief-making Twitter user, social media hasn't stopped wringing its hands over what is and isn't visible. Particularly unnerving to some viewers of the photo has been their inability to re-see the initial shininess that they had first perceived and to unsee the painted streaks that – look away now if you don't want to know the score – are really what's responsible for conjuring the appearance of glossiness.
Though the deceptively simple optical trick has caught the world by surprise this week, in fact the principle behind it is a very familiar one to many, even if they don't realise it. The illusion is a product of our suggestibility as a species – an innate impressionability with which our brains are hardwired. Put simply, our minds are desperate to comprehend larger patterns – an evolutionary proclivity that has helped us survive and thrive.