
Rotating snakes

This colorful illusion is sure to make your head spin. Look at the edges of the snakes – while the one you’re staring at will seem static, the lines around it will appear to rotate. This optical illusion works due to microscopic eye movements called saccades. These are rapid movements of the eye that change the point of fixation.
Ponzo illusion

Look at the two yellow lines in the image above. They’re different lengths, right? Wrong! Believe it or not, both of the lines are the exact same length. Cover up the tracks, and you’ll be baffled at how easily your brain can lie to you.
A face or a peacock?

Optical illusions are a wondrous thing, showing how differently people’s brains process imagery. Some people see one image, others see both, their brains switching between the two simultaneously. The way these illusions work is more to do with how your brain processes information, rather than how your eyes work.
The famous blue (or is it gold?) dress

Who could forget the infamous dress that divided the nation? Some people say the dress is clearly black and blue, while others claim they see white and gold. Supposedly, those who are night owls will see blue, whereas early risers will see white – all due to the amount of sunlight you recieve. Eventually, the dress was confirmed to be black and blue.
Optical illusions can save lives

This image can be found in Canada, implemented by authorities in an effort to ensure drivers stay aware of their surroundings. The further away from the image you are, the more it looks like a child in the middle of the road – a clever trick to make sure that drivers watch their speed.
How many legs does the elephant have?

We all know elephants only have four legs but this optical illusion can make it seem as though there’s more. Some people even see eight! In truth, the artist purposely used empty space to play tricks on our eye – there truly are only four legs. Still confused? Cover up the elephant’s feet.
Face or vase?

What do you see first: a vase or two faces looking at each other? Your brain has to make a snap decision about which part of the image is the focus, and which part is the background. If your brain picks up black first, you’ll see the vase. If your brain focuses on white colors first, you’ll see two faces.
Young or old?

What do you see? A young woman looking over her shoulder, or an old woman looking to the side? If you can’t see the elderly lady, look at it this way – the necklace is the woman’s mouth, and the ear is the old woman’s eye, with a big nose doubling up as the younger woman’s side profile.
A hole in the hand

Optical illusions can make for neat party tricks. Anyone can do this trick – just grab some non-toxic paints and a brush. Start with a hole in the middle of your palm, and contour lines going outwards. Add more detail as you go on and voila! From the right perspective, you can trick people into thinking there’s a bottomless pit in the center of your hand.
The 3D ladder

The ladder in the image above isn’t actually sticking out of the paper – the whole thing is entirely 2D! The clever artist uses his skill to play with perspective, using shadows to manipulate the mind into seeing something that isn’t truly there. The best part is, this illusion compromises of just straight lines and a piece of paper – so anyone can do it!
Spinning and pulsing

This example shows how easy it is to warp your own perception. Many of the first optical illusions were in black and white because it doesn’t take much information for the brain to panic. Keep your eyes locked right in the center and slowly move your head around, as parts come in and out of focus, the striped pulse.
So many oreos

Another piece using the principle of just having too much stuff to focus on, these hypnotizing cylinders might throb, roll clockwise or counterclockwise, or even do both at once. Bursts of color from black and white images are a bizarre phenomenon, showing us that, regardless of the awesome power of the human brain, we’re not perfect.
Flipping men, ey?

Simple illusions like this are the bread and butter of caricaturists and newspaper comic artists. They’re usually accompanied by a prompt to be part of the 2% of people smart enough to see the secret, which is just mean and elitist so spoilers; Flip him upside down. There you’re a genius now, go out and save the world after you share this on Facebook.
Dr Angry and Mr Calm

This real-life Jekyll and Hyde situation was created by two scientists to test how facial perception can be influenced. By moving away from the image, the faces change to each other’s expressions! It’s done by overlapping them with both faces, only with different amounts of information on various frequencies, that our eyes adjust to with distance.
Clops or hops?

First and foremost, creating illusions on a computer is quite easy, you can control everything down to the pixel, wipe mistakes instantly and save and return whenever you wish. This pencil sketch went viral for the strength of its illusion and artistic creativity, but no artist has ever been identified. If you’re struggling, look at it like a confused dog.
All aboard

This demonstrates one of the fundamental ideas behind how optical illusions work. The Ponzo illusion as seen above features two red lines that almost certainly look different lengths, with the top being longer. Both lines are the same size, but the linear nature of the perspective makes it difficult to tell, as the top looks further away.
Kanizsa triangle

On top of being a great design for a cult about space, this is also an example of how our brain tries to fill in negative space. Although there is no triangle in the center, it’s only implied by the lack of a triangle, your eyes pick up the contextual information surrounding it and can’t help but tell you there is a triangle there.
Please stay still

Truly one of the most infuriating images on the internet. Regardless of where the eye settles, the rest of the image starts acting like someone put Earth, Wind and Fire on the playlist. The colors used beneath each individual dot act like highlights and shadows, which create the illusion of a 3-d image, the eye struggles to keep track of the orientation of each one.
Self-repairing wall

Created by a Japanese neuroscientist, this crooked grid will start fixing itself as you fixate on the center. This is thought to happen because the brain tends to order so, as you focus, your peripherals are filled in and you see something close to what your brain expects to see.
Simple and effective

It might look like the background from a PlayStation One game menu, but fortunately, it has the interactivity of one too. Look in the center and slowly move your face closer to the screen (careful not to bump your face!) and notice how the gradient in the middle suddenly blooms out to the entire image!
Big dot, small dot

Another classic from the early internet, this had people scratching their heads before their dial-up modems had even finished loading the image. Scale is difficult to judge without proper visual context. This piece uses intentionally mismatching sizes with the blue spots, which makes it look as though one of the central circles is bigger than the other.
Life in watercolor

These charming little splodges take advantage of something called the watercolor effects. It looks as though they have been shaded in around the edges, but in fact, the shapes only have colored outlines. By using two complimenting colors, the brain fills in the rest of the shape with a gentle gradient.
Hold on – I’m spiralling!

This hypnotic spiral is actually nothing of the sort. The image shows a series of concentric circles that simply get smaller as they reach the middle, but the overlapping colors of the gingham-like background stop the eye from perceiving them as such. Trace a few of the circles with your finger and find out!
O, Christmas tree

Color is one of the easiest ways to engage the mind, we think about complimenting colors all the time when creating things, since the brain finds certain combinations pleasing and easy to look at. Here, it might look as though the Christmas trees are two different shades of green, but they’re the same.
Pivot… Pivot…PIVOT

Perspective and depth are difficult to judge in two-dimensional space, as this image proves. By skewing the tables at precise angles, it seems impossible that they are the same size. You would swear the left is lengthy and the right is girthy, but the plank of wood fits perfectly over both.
Hidden text

At the distance you’re probably reading this article, this picture may just look like a series of blocks and shapes. Put some distance or distortion between you and the image, however, and you see it has been specifically designed to contain text in its negative space!
Side-eyeing

Other than being just a little bit cursed, this effect shows how blur and shadows can imply details that aren’t really there. On the left, it appears as though the woman is looking to the side, but the un-blurred image reveals she was Medusa the entire time. The secret to beating her isn’t a mirrored shield – just being short-sighted!
Checkered bulge

You know how this works by this point, there is no bulge in the middle of the left image and your brain is just turning to mush from having to process so many things designed to upset it. Regardless, it’s astonishing how effective the placement of the dots is in creating a sense of depth and curvature on the checkerboard.
Criss-crossing colors

Another example of color changing your perception, take a look at the grid lines and see what color you think they are. The top left is reddish, below that they look green. They’re all the same color, a dull grey, but the lovely pastel backgrounds make them appear a different tone. Utterly magical.
The floating square

The detail and fidelity of a picture have a lot to do with how we perceive it. When shapes have white and black sides, we can’t help but try and judge depth since it looks like shadows and highlights. That’s what makes this cube pop, seeming to float above the minefield of spiky diamonds.
All snakes, no ladders

This is a spruced-up version of one of the most classic optical illusions on the internet. The famous spinning snakes are one of the most powerful moving still images you can find, and this version enhances it by understanding what makes it work. By enhancing brightness and adding colors for a chromatic shift effect, the snakes never seemed so funky.
Count the dots

Sound easy? Well, it pretty much is, there are only 12. You’ll notice though that it’s incredibly difficult to see all of them at once. Focus on one of the corner dots and try to catch the opposite one in your peripheral vision. It’s not exactly clear how this phenomenon works, but we know our eyes process information imperfectly, especially outside of our focus.
Hay, what’s going on here?

Another classic from the pre-internet era, this illustration is famous for stumping, or hoofing rather, pretty much everyone who sees it. Officially there are seven horses in the image, though many people contend there are only five. It’s humbling that, even before social media, people would tell artists they were wrong about their work.
Mixed messages

Be honest here because scientists say the first thing you read determines absolutely everything about your love life, career ambitions, and choice of pizza topping. That’s a joke, it’s more of a simple graphic design trick if anything. The way the brain can shift between the readings for a few seconds, making the other text seems impossible to see, is impressive.
Nod along

Time for some more interaction! As per usual, stare at the black dot in the middle, then rock your head back and forth like you’re watching the Bohemian Rhapsody scene from Wayne’s World at about 40% speed. You’ll notice that, depending on the motion, the two circles spin in opposite directions in time with your movement.
Spot the splotches

This is easier to spot for women, to the point it might not even look like an optical illusion. It can take a while but once you see through the little splotches and get to the text, you’ll wonder how you ever even missed it in the first place.
Scene or portrait

This wonderful little illustration uses perspective and its black-and-white palette to create two pictures that can flicker back and forth with a little dart of the eye. The Native American man’s eye line sits on the back of the Inuit’s head, so by looking to the right means seeing the hood contrasted against the cave. A simple but lavishly detailed piece.
Eye eye, Captain

While more of a puzzle than an illusion, the effort put into creating the effect of the sails slowly morphing into clouds as the horizon expands and the pillars appear is worthy of appreciation. Try and spot which ship in the sequence is the final one before it becomes only cloud! And yes, there’s a correct answer.
Make it disappear

As simple as they come and still pretty astounding, this one probably works best on your phone. First, look at it from afar and notice the small dark area of the gradient around the dot. Now move your face closer and focus on that spot. You should see the darker area start to disappear before vanishing entirely if you manage to stay concentrated.
Back to school

This illusion is most commonly seen in mathematics class since it’s easy to draw and they have to do something to make math interesting. The diagonal line through the left parallelogram looks much longer than the one opposite, but they’re exactly the same size. You were probably taught why and forgot it, so you’ve failed the one instance in life math would have been useful.