The image, which features a number hidden within a a black and grey striped swirl, was posted to Twitter with the question “do you see a number? If so, what number?”.
A mind-boggling optical illusion has left people baffled after going viral online.
The image, which features a number hidden within a black and grey striped swirl, was posted to Twitter with the question “do you see a number? If so, what number?”.
However, the confusing puzzle has sparked a debate online, with many seeing very different numbers compared to their friends, according to the Mirror.
For example, one commenter said they could see the number 45283, whereas another only saw the number 528 until they lay their phone flat, which revealed “another 2 or 3”.
A third said they could also see 528 when wearing their glasses – but got 45283 when they looked at the picture without them on.
The illusion was tweeted by Twitter user @benonwine and has since prompted a range of responses from perplexed puzzle solvers.
One person wrote: “8452839 and I bet the right number has been found. The first digit is the trickiest because it could be a 3, 6, or 8. I’m plumping for the 8”.
Another said, “52839, it keeps changing”, while a third person insisted, “3452839. It’s easy to miss the 3 on the front and the 9 on the back, but they are there”.
However, despite many seeing something completely different altogether, the seven-digit figure at the heart of the swirl is actually 3452839.
As reported by the Mail Online, this illusion works by playing on contrast sensitivity, which is understood to be a very important measure of visual function.
Contrast sensitivity allows people to perceive differences between objects and their backgrounds, in ways that prove very useful in everyday life. For example, while driving during foggy conditions.People with high levels of contrast sensitivity are said to be more likely to be able to see all seven digits of the number straight away.
At the other end of the scale, low levels of contrast sensitivity can be symptomatic of eye conditions such as cataracts or glaucoma.