Do you see a blue and green swirl in the image? (Photo: JOLLY / YouTube)
Optical illusions are clever ways of testing our powers of perception and can often be interpreted in different ways. It is said that how we see such images reflects how our brain works - and in turn, this is said to reveal traits about our personality.
The left side of the brain is linked with being more verbal and analytical, and is better at tasks such as reading and writing, while the right is said to be more visual, intuitive and creative.
How we see images with multiple interpretations is thought to show whether the right or left side of the brain is more dominant, and in turn this is said to indicate our characteristics, such as if we are more extroverted or introverted.
But there are other optical illusions that are designed to play a trick on the mind.
How many colours do you see?
This coloured swirl illusion posted on Reddit has been widely shared across the internet and has left viewers baffled.
The image appears to depict two different coloured swirls decreasing in size against an orange background.
On first glance the two swirls look like they are both a different colour, with most people seeing blue and green spirals. However, the swirls are actually both identical in colour.
A closer look at the image in a YouTube video shows that the swirls are neither blue or green, but are in fact both a turquoise colour.
The reason the colours appear different is because our brain interprets the colour of an object by comparing it to colours surrounding it.
In this case, the swirl which appears blue has thin pink lines running through it, while the swirl that appears to be green has thin orange stripes going over it.
The pink and orange overlapping lines cause our brains to think that the spiral shapes are two different colours when they are actually both the same.
Zooming in on the image and looking at it more closely helps to show that the colours are identical, showing how easily our brains can be fooled.
Reddit users were left stunned by the image, with people saying their brain was finding it hard to accept.
One user wrote: “Hands down one of my favourite illusions. No matter how many times I see it my brain can’t accept that they’re the same colour.”
Another said: “My brain is definitely looking for a way out of this one, even after seeing the final image. Craziness!”
“My brain hurts”, someone else commented.
“Damn I saw it the 2nd time and never again”, another added.
The image is very similar to a dress illusion that went viral on the internet several years ago, with some people seeing it as white and gold, while others could see blue and black.
The image, which was first posted on Tumblr, quickly spread across Facebook and Twitter feeds across the world as people argued over what colour it was.
Cedar Riener, associate professor of psychology at Randolph-Macon College, explained to BuzzFeed that the differences in colour perception are related to how our brains interpret the "quantity of light that comes into our retina."
This luminance is a combination of how much light is shining on an object and how much it reflects off of the object’s surface.
It means that our individual sensitivity to the background lighting of the photo affects how we see the object in the image.
Reiner explained: “Some people are deciding that there is a fair amount of illumination on a blue and black (or less reflective) dress.
"Other people are deciding that it is less illumination on a white/gold dress (it is in shadow, but more reflective)."
Want more visual magic? Check out more mind-bending optical illusions.