Magic Eye pictures like these are great fun, but they can also be informative about you and your health.

Hands up: who remembers when Magic Eyes were all the rage back in the 1990s? As you may know, these images actually contain a three-dimensional shape hidden within the picture. But Magic Eyes are not only fun; they can apparently tell us something quite important about ourselves, too.

Image: Instagram/lamiayena / Nevit Dilmen/CC BY-SA 3.0

Whether or not you recall the Magic Eye craze of bygone years, you will most probably have seen one of the pictures. The premise is simple: gaze at an otherwise random collection of colors and shapes and find yourself surprised by a three-dimensional shape that seemingly leaps out. And if you’ve tried them with family or friends, you will also know that there are invariably one or two people who just can’t see it.

But there’s a proper technique to viewing them, of course. On the company’s website, Magic Eye writes, “Hold the center of the printed image right up to your nose. It should be blurry. Focus as though you are looking through the image into the distance.”

Image: Instagram/magic_easy_colors / Instagram/magic_easy_colors

There are further steps to complete before the 3D image should become apparent. But when it does, you can admire it in all its glory. The Magic Eye website continues, “Once you perceive the hidden image and depth, you can look around the entire 3D image. The longer you look, the clearer the illusion becomes. The farther away you hold the page, the deeper it becomes.”

Image: Instagram/magic_easy_colors / Twitter/Junio Puzzles

So, as we’ve seen, there’s a technique involved in viewing Magic Eye images. But where did the whole idea even come from? Why were we all suddenly staring deeply into squiggles and swirls in the last decade of the 20th century? Well, scientists were using Magic Eye images – known as stereograms – long before they became a popular leisure activity. In other words, they were not designed solely for our amusement.

Magic Eye pictures are actually stereograms themselves. Dr. Bela Julesz is credited with inventing the very first random dot version – in black and white – way back in 1959. And he did so in order to test stereopsis, which is the human ability to see objects three-dimensionally. Stereopsis involves the blending of two similar pictures into one – allowing us to view something in 3D.

Dr. Julesz’ work was taken up by a student of his called Christopher Tyler. With the assistance of Maureen Clarke – a computer programmer – Tyler was able to further develop stereograms and create a single-image version. And that is exactly what Magic Eye pictures are. Yet Dr. Julesz, Tyler and Clarke were all working towards developing a better understanding of how stereopsis works.

But why were stereograms created in the first place? Well, scientists were interested in studying the concept of depth perception. They wanted to learn more about how our eyes turn different pictures into a single coherent one. In 3D, of course. The width between our two eyes is known as pupillary distance. And according to the retailer Superdrug, anywhere between 58 and 64 millimeters is considered to be normal.

J.C.A Read from Newcastle University’s Institute of Neuroscience put it best in his paper Stereovision and strabismus. He wrote, “Binocular stereopsis, or stereovision, is the ability to derive information about how far away objects are – based solely on the relative positions of the object in the two eyes.”

Stereopsis, therefore, is a pretty crucial ability. In fact, without it, we’d constantly have double vision. But considering stereograms are used to analyze visual depth and three-dimensional sight, it is interesting that they aren’t 3D themselves.

Image: LosHawlos at German Wikipedia / CC BY-SA 3.0

Interestingly, the original random dot stereogram actually involved two pictures. The website Mental Floss writes, “[Dr.] Julesz would generate one image of uniform, randomly distributed dots. Then, he’d select a circular area of dots within the image and shift that area slightly in a second image. Someone viewing the two pictures side by side perceive a circle floating above the background – even though the random dots had no depth cues. This supported his idea that depth perception happened in the brain, and not in the eye itself.”

Two decades later Maureen Clarke and Chris Tyler worked out that they could achieve the same results with one image. The Mental Floss article notes, “Their research revealed what was happening in the eyes and brain when viewers looked at stereograms. When presented with an image like this, your eyes might each look at two different points, but because the image is a repeating pattern, the brain is tricked into thinking that the two spots are the same thing. The brain then perceives depth, with the two points as being on a virtual plane behind the pattern.”

Image: LosHawlos/ Mr. Anderson/CC BY-SA 3.0

But soon the concept behind these images was taken and applied for a rather different purpose: to create fun optical illusions. And that’s where Magic Eye came in. Developed in 1991, it was the brainchild of engineer Tom Baccei, 3D artist Cherri Smith and Bob Salitsky – a programmer. And these three individuals began building upon the research that had gone before them.

Image: letsgetprocessing / magic_easy_colors

“Magic Eye… works by manipulating a repeating pattern to control the perceived depth and hide a three-dimensional image in a two-dimensional pattern,” Mental Floss writes. “[It] starts with a programmer creating the hidden image… as a grayscale, smooth gradient depth map where dark points that should be furthest away are darker and closer points are in lighter shades. Then, they create a 2D pattern to camouflage that image.”

Image: Twitter/Junio Puzzles / Instagram/dvizhzs

But they are not done just yet. The publication continues, “Finally, a computer program using a Magic Eye-patented algorithm takes the image model and the pattern and orients repeating patterns to the intended depth of the hidden image. When someone looks at a Magic Eye, the repeating pattern feeds the brain the depth information encoded into it, and the brain perceives the hidden picture.” And that, dear reader, is how it all works!

Image: invariavelmente / 3dmovieman-blog

It’s safe to say that Magic Eye products have been successful. The company’s first three books were on The New York Times Bestseller List for an incredible 73 weeks between them. Another Magic Eye book broke German publishing records, too. There have also been 30 books in total and over 20 million copies have been sold worldwide, according to the company.

But none of this explains why some people simply cannot see the 3D image in Magic Eye pictures. Well, there are two potential reasons for this, Mental Floss claims. The first is that there is a malfunction somewhere in terms of your stereo or binocular vision. It could be that you could have a misalignment in one or both of your eyes.

There could be several reasons why you might have a binocular or stereo vision impairment. Mental Floss notes that it could be caused by astigmatism, or even cataracts. Of course, it is always wise to seek medical help if you believe there to be any type of problem with your eyes. But do not automatically think that if you cannot see a Magic Eye picture properly that you have a debilitating eye complaint. For the truth could be far less worrying.

And there is a second reason why you not be able to see the 3D image contained within a Magic Eye picture. And that is simply a case of poor technique. You have to know how to look at them. Essentially, it’s a case of focusing your eyes on the image for a length of time and experimenting with moving the image closer and further away until you can see it properly.

So rest assured, just because you may not be able to see the image contained within a Magic Eye picture now, there is still hope. A little practice should suffice, and then things should get clearer. But, at this stage, wouldn’t you like to try and see some images for yourself? Perhaps you’re unsure if you can see the magical visions contained within. So, without further ado, here are 20 examples of popular Magic Eye pictures. Do they work for you?

20.

A first glance of this Magic Eye picture reminds us of an old television set. For those old enough, do you remember what you would see on the screen when the TV wasn’t tuned in properly? But dig a little deeper into this image and you’ll find something much more fantastical: a rearing unicorn, no less.

19.

Some Magic Eye pictures these days are actually moving images. This red image – which dashes across your screen from left to right – contains a moving shape hidden within. Relax your eyes, continue looking and you will be amazed by the vision of a shark swimming across your screen. On the hunt for prey, perhaps?

18.

Some Magic Eye pictures reveal images that are more impressive than others. It’s all a matter of opinion, of course, but many people will agree that this aqua-themed shot is particularly impressive. Gaze into the abyss and you will soon discover the name “Leyla” partially submerged in water.

17.

Stereograms are all about visual depth perception. And they don’t come much better than this particular illustration. The reveal is a winding spiral contour, which could be interpreted as any number of things. Mesmerizing.

16.

The beauty of a Magic Eye picture is that, unless you have been given some sort of pre-warning, you never know what’s going to leap out at you. It might be worth pointing out that this example wouldn’t be out of place around Halloween. The 3D image within is a rather intimidating-looking skull.

15.

Magic Eye images are distinctly 1990s. But this example contains a more modern twist as it reveals something that has become very much ubiquitous in the 21st century: an emoji. Gaze into the distance of this particular picture and you will soon be met by a rather cheeky tongue-out emoticon. It’s a great example of the playful nature of Magic Eye pictures.

14.

If we are being honest, not every Magic Eye image will have you gasping “wow” in amazement. While the concept is always interesting, some of the 3D images are just a little boring. But that’s not the case with the majestic looking feline that reveals itself in this example. You can almost reach out and pet it.

13.

Animals are a particular favorite of the makers of Magic Eye pictures – with everything from horses to sharks immortalized by the classic series. As you can see, this picture conjures up visions of frozen woods. And the animal lurking within would be well at home there: it’s a lone wolf.

12.

Would you agree that there is a definitely psychedelic edge to this particular picture? It’s like something you would find on a 1960s psychedelic album cover, for example. But gaze within, as you are encouraged to do, and a pair of bells should rise up out of the madness to meet you.

11.

Whether this particular picture was a stereogram or not, it would quite possibly attract attention as a 2D image. The sequence of swirls or spirals running left to right is then interrupted by what could be described as a ripple effect – akin to a stone being thrown into a pond. But it is a stereogram. And the reveal is another swirl or spiral.

10.

Often the constituent parts of a stereogram are interesting in themselves. That’s certainly the case with this example, which appears to be made up of a number of wild animals that wouldn’t be out of place on the African Savannah. And neither would the majestic-looking 3D elephant that reveals itself upon closer inspection.

9.

Quite often with a Magic Eye picture, the 2D scene gives absolutely no clue as to what 3D image will leap from the page or screen. That’s half the point I suppose. So, you would be forgiven for imagining a beautiful golden field of wheat or corn at first glance of this particular picture. Yet it’s the rather noble image of a hawk that reveals itself.

8.

This stereogram has a lovely reveal. The picture is rather regal in itself with all of the shimmering golds conjuring up images of a crown or some other piece of finely crafted jewelry. But then, of course, the 2D pictures on display at the bottom are a bit of a giveaway that the image within is indeed itself a ring.

7.

What’s the first thing you think of when you look at this particular image? A swarm of bees perhaps? Or a Van Gogh field of sunflowers? Whatever it is, it’s likely to have a summer vibe. Not that an umbrella would be totally out of the question in most places during that season. For that’s exactly what shows itself.

6.

If you stare into this image and are immediately reminded of the coat of a particular African animal, then that is exactly the point. And within moments – as long as your technique is right, of course – you should be met by the rather majestic sight of a trio of zebra. A family, perhaps?

5.

This one will help pick you up in the morning. The coffee beans are, of course, difficult to avoid. But get your divergence right while looking at the picture and you’ll be met with a nice hot beverage of some sort.

4.

This is an intriguing-looking image in itself. But use the required technique and you are soon met with the unmistakable contours of one of the world’s most iconic-looking buildings. Want a clue? It’s in India. That’s right. What you will see is none other than the gorgeous piece of architecture that is the Taj Mahal.

3.

There’s definitely something fantastical about stereograms, don’t you think? And this example of the Magic Eye concept certainly plays on that otherworldly theme. The majestic creature that rises up to meet us here is none other than the famed Pegasus of Greek mythology.

2.

This one is a nice little variation of the theme of the stereogram. The image of what might or might not be earth reveals a message that could well be deeper in meaning. Interestingly, the letters that appear say “H20.”

1.

Your first instinct here might be to assume this is not a stereogram at all, but a close up of the stitching contained within a Christmas jumper. Yet these particular colors combine well to create a chilly atmosphere in which the 3D reveal doesn’t look out of place. For reference, the image is of a downhill skier in full flight.