Iconic dress brainteaser has a sequel as people can't work out colour of flip flops

Most people remember 'the dress' that was either blue and black or white and gold, depending on your perspective. The 2015 viral phenomenon sparked debates across the world with internet users sharing what they saw, revealing differences in human colour perception and even becoming a subject of scientific investigation.

But it seems 'the dress' isn't the only item of clothing to have caused a stir online. Now, a pair of flip flops has caught the attention of Reddit users. Sharing a picture of a pair of Havaianas on sale in a shop, one user said: "Is this another THE DRESS photo?" In response, one user said: "I only see a pair of blue and black sandals. Does anyone see something else?"

In agreement, someone else said: "No, they're black and blue! What's wrong with your eyes."

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However, another claims they can see white and gold - reigniting 'the dress' debate. They said: "Every time with these I only see white and gold!"

One more added: "Same here. White and gold with a shadow over it. Never blue and black; I honestly thought the dress was a prank at first."

Confused by the entire thing, another user said: "Right there with you on that until I watched it change colours in real time for myself… it was white and gold, scrolled down and back up and it was black and blue.

"The person I was with still saw white and gold, I have no clue how to explain what happened."

One more user said: "I believe it's blue and black, but I can only see white/gold as well.

"The screwy part is, the soles of the shoes next to it in the background look black to me. I can tell those are black.

"I wonder if this has something to do with people who have exposure to lots of bright sunlight.

"I live northeast and not on a beach, maybe if I lived in California and was exposed to products/photos taken in bright bright light more my brain would understand it.

"I'm also curious what colour a computer would say those shoes are. Like the gold part to me is so clearly not a black colour. I have no clue how something in a shadow can look that tan/gold if it's supposed to be black."

According to New York University neuroscientist Pascal Wallisch, the differences in perception are due to our assumptions about how the dress was illuminated.

Speaking about 'the dress', he said: "The original image was overexposed, rendering the illumination source uncertain.

"As a result, we make assumptions about how the dress was illuminated, which affects the colors we see.”

"Shadows are blue, so we mentally subtract the blue light in order to view the image, which then appears in bright colours—gold and white.

"However, artificial light tends to be yellowish, so if we see it brightened in this fashion, we factor out this colour, leaving us with a dress that we see as black and blue.

"This is a basic cognitive function: to appreciate the colour on an object, the illumination source has to be taken into account, which the brain does continuously."

At the time of writing, the Mirror has been unable to confirm whether the flip flops are, in fact, blue or black or white and gold. What colours do you see?