Curvature blindness and 5 other optical illusions that will blow your brain

We hate to break it to you, but if you see zig-zags in the image above you have curvature blindness. While the image appears to show a series of curves and zig-zags, the lines are in fact all wavy.

But don't worry – while this may sound terrifying, it simply means that your brain is processing the lines in different ways. By staring directly at the zig-zags, it becomes clear that they are in fact slightly rounded. And we all experience curvature blindness.

This illusion was created by researchers at Chukyo University in Japan, who coined the phrase "curvature blindness". While the reason for the phenomenon is unclear, lead researcher Kohske Takahashi surmised that it's likely because the brain finds it easier to process corners when it is befuddled by a complex image.

Here are a few more optical illusions that highlight how easy are brains are to confuse.

The castle

A phenomenon known as "after image" is at work in this illusion. First, click on video below to experience it.

You will see that by staring at the dot in the centre of the purplish green image, the brain is able to collect enough information to apply colours to the monochrome image, filling in everything from the blue sky to the vibrant grass near Dunstanburgh Castle.

This works in a similar way to a film negative. Take your eyes off the image for a second, and it will once again appear in black and white.

The green and blue swirl

Brace yourself to be shaken to your very core. There is a bright blue swirl and a lime green swirl in the image above, right? Wrong.

The twists in this mind-bending illusion are in fact both exactly the same colour. (That's hex code #00ff96 for the colour conversion geeks out there).

This illusion is all about how our brains understand the context of colours. The orange stripes don't pass through the blue spiral, while the pink stripes don't cross the green. As a result, we see a swirl of blue, green and pink.

The oily legs

We know what you're thinking: "Gah, why are these legs so weird and oily?!" They're not. It's just white paint. This illusion went viral in 2016, when an art student called Hunter Culverhouse posted the image on her Instagram.

Look closely, and you will notice that what appears to be light shining onto the legs is in fact streaks of paint. Once you see it, you can't unsee it.

Culverhouse told Insider that she didn't even mean to create the effect.

"[I] had some white paint left on my brush and put random lines on my legs," Culverhouse explained. "It turned out to be a completely confusing picture for everyone on the internet."

The red strawberries

Mmmm, those red strawberries look delicious, don't they? Well, we hate to shatter the illusion (pun intended), but your brain is lying to you, again! (Yes, a pattern is forming here).

While the strawberries appear to have an off-red hue, there is in fact no red in the image at all.

It was shared by Akiyoshi Kitaoka‏, a professor of psychology at Ritsukmeikan University, to explain the phenomenon of 'colour constancy'. When faced with this image, your brain decides whether to prioritise the colour of the object or the colour of the light, knowing that former is more important than the latter. Your brains sees strawberries, so it fills in the colours that it knows strawberries are.

Below is an image mocked up by writer Carson Mell on Twitter, showing the colours that make up the image.

"You brain says, 'the light source that I'm viewing these strawberries under has some blue component to it, so I'm going to subtract that automatically from every pixel,'" Bevil Conway, a neuroscientist at the National Eye Institute, told Motherboard.

The cigar illusion

At first glance, this image looks like a standard brick wall. But look really, really closely at this image you will – eventually – notice that it shows a cigar poking from the wall.

As the grey ash blends in with the cement, the brown paper looks like a gap between the bricks.