X-Rated Optical Illusion Goes Viral: 'Tell Me It's Not Just Me Who Sees It'

A real-life optical illusion has gone viral after being posted to Twitter by a woman seeking reassurance she isn't the only one with a dirty mind.

The image shows a shaft of sunlight beaming through a naturally-made stone tunnel onto a stream and some surrounding undergrowth.

It's undoubtedly a picture of stunning natural beauty.

However, it's also an image that, upon first glance for some at least, appears to be depicting a shaft of an altogether different kind.

The X-rated illusion was shared to Twitter by a user who calls herself Mairhead and posts under the handle Midge1415.

"Tell me it's not just me who sees it," she wrote alongside the tweet. "Please, I worry about me."

At the time of writing, the post has earned over 17,000 interactions on Twitter, with fellow users flocking to reassure the original poster that she is not alone in seeing what she saw.

In fact, most saw little else.

Netty0779 wrote: "I'm trying to work out what it actually is cos it can't be what I'm seeing."

MarianTrevilli1 agreed: "I'm embarrassed to tell you how long it took me to see the shaft of sunlight."

Elsewhere Chuyungo admitted: "There are some things once seen that cannot be unseen!" while StephenJenkins1 said: "Occasionally a photograph is just taken at the perfect time."

British politician George Galloway even weighed into the comments, quipping: "This is unsolicited please don't send me more."

Many comments also came flooding in from fellow users eager to share similar examples of this particular phenomenon.

Marie Fairclough showed social media her three-year-old granddaughter's attempt at a picture of her mum holding a coffee.

Nicola Ellen recalled the time she received a chocolate santa.

While Haggy Hagarth offered up an unusual snap of her daughter's baby Bambi toy.

John Clark, meanwhile, highlighted a rather unfortunate design flaw in London's Westminster Bridge.

Away from the striking imagery, arguably the most apt response came from a user posting as MrsM_Weegie, who wrote: "We're all juvenile and smutty but it is funny."

Speaking to Newsweek, Mairhead, who according to her Twitter bio is from Ireland, briefly explained the image's origins. "It was sent to me via WhatsApp and I found it funny," she said. "Funny what takes off online."

Optical illusions may be puzzling on the eye, but there is a logical explanation for why they can occur. It's all to do with a mix up in the way the human eye communicates what it sees to the brain.

"Our eyes and brain speak to each other in a very simple language, like a child who doesn't know many words," Professor Cedric van den Berg from the University of Queensland in Australia, explains. "Most of the time that's not a problem and our brain is able to understand what the eyes tell it."

"But your brain also has to 'fill in the blanks,' meaning it has to make some guesses based on the simple clues from the eyes," he adds. "Optical illusions happen when our brain and eyes try to speak to each other in simple language but the interpretation gets a bit mixed-up."

This is not the first time an optical illusion has gone viral, of course.

Previously, less X-rated efforts have included a cat who appeared to have an arm going through it and a young girl who was pictured seemingly sinking into the sidewalk.