Can you see this?

[Flyingcursor]

Pretty cool. I wish I knew how to make these.

[Wombat]

I just tried an experiment. Depth vision depends on our having binocular vision so I tried closing one eye at a time once I got the image going. Whichever eye I closed, the image went away but returned as as soon as I opened it again.

[Whistlin'Dixie]

I love magic eye.

This one is cool!

I can see magic eye images so easily, that once my eyes are "right" (takes only a couple of seconds) I can flip thru a picture book almost as fast as any regular book.

My sons can do it, too.

M

[Wanderer]

I just tried an experiment. Depth vision depends on our having binocular vision so I tried closing one eye at a time once I got the image going. Whichever eye I closed, the image went away but returned as as soon as I opened it again.

It's definitley depth perception. I don't have any measurable stereovision, due to the fact that one of my eyes was crossed for the first 10 years of my life or so. Like all those other neat 'vision tricks', I can't see this one. I also don't see a sausage when I hold my hands up in front of my eyes. And I don't see a hole in my hand when I look at my hand through one eye while looking through a paper towel tube with the other. :Sigh: I miss all the fun.

[Joseph E. Smith]

Very cool. I love these things. A swimming shark alright... looks like a Bull Shark.

[Innocent Bystander]

Pretty cool. I wish I knew how to make these.

There's a Graphics application called CorelDraw, which has an option for picking an image out on a random noise background.
A shark like the one in the image, but not moving, is going to be at least six separate images overlaid. In fact, if you look carefully at the shark, you can see that it is really much like a rough contour model.

After you've made two or three of these overlaid images in random noise, you can start choosing more elaborate background patterns, and editing them to give the image you want.

And that's for a single fixed image. For a moving GIF you need to overlay a number of images so they move. But it's just more of the same.

It's a lot of work. An easier approach for those wanting quick results, is to draw a picture, copy the whole thing so there are two pictures side by side, and edit each of them so that they stand out as one image in stereo vision. I made one of a cartoon pussycat and made my daughter squeal with delight. (Actually that's not difficult.)

A good sample to practice with is two ellipses joined by two straight lines.
Two images like this, side by side and slanted about five degrees, can become the image of a hollow cylinder. This is so easy, it can be done with a pencil and paper.

[Cynth]

I just get my face somewhat close, maybe a little more than a hand's length (left my reading glasses on), initially focused behind the screen, let the pixelly box fill my vision, stopped any kind of attempts at focussing anywhere, and then let my eyes feel like they're going "flabby" or "melting". The shark soon materialises.

I tried that.

Didn't happen. So I took off my glasses, focused both my eyes on the tip of my nose, tried to let my vision wander, held my breath in anticipation and very soon I could hear the theme from "Jaws" playing in my head.

Nearly there, try again tomorrow.

Slan,
D.

Whoa, sir, I think you actually may have gone past it !

Sometimes I see one shark swimming, and sometimes like Wombat (I think) I see a fish in the foreground and a spikier shark in the background both moving---then it is very hard to see the singe shark again. It can take about a minute before I see them. Not crossing eyes or moving close to screen. The "flabby" focus seems to decsribe how it feels, very relaxed. I was told once that I didn't have very good depth perception. Don't know if that's true or not.

[djm]

I saw a shark. But I thought I saw another fish (or something long and thin) in front of the shark. Maybe a smaller fish.

I think that if you look closer you will see that this is not a smaller fish, but the shark's pectoral fin on the near side (its 3D, afterall ).

djm

[I.D.10-t]

Cool. Yeah, I'd never seen one of those moving.

I have, in ascii.

http://www.kammerl.de/ascii/AsciiStereoMovie.php

Oh, and for funASCII stereogram

[djm]

Maybe its just me, but the ASCII one seems to be to large scale for me to be able to hold the vision for very long (I mean, versus the dots type).

djm

[Wombat]

I saw a shark. But I thought I saw another fish (or something long and thin) in front of the shark. Maybe a smaller fish.

I think that if you look closer you will see that this is not a smaller fish, but the shark's pectoral fin on the near side (its 3D, afterall ).

djm

I was wondering why nobody else could see the second fish. I'll have another look; maybe you're right. If it is a fin it's a bit clunky.

[Nanohedron]

I saw a shark. But I thought I saw another fish (or something long and thin) in front of the shark. Maybe a smaller fish.

I think that if you look closer you will see that this is not a smaller fish, but the shark's pectoral fin on the near side (its 3D, afterall ).

djm

I was wondering why nobody else could see the second fish. I'll have another look; maybe you're right. If it is a fin it's a bit clunky.

Wombles, do you mean "in front" as in from the viewer's perspective (IOW, the phantom fish would be to the shark's left and so in the foreground, not to the viewer's left, i.e., preceding its nose)? If that's the case, I saw it this time, but soon realised it was an incomplete resolution of the intended effect. What I saw in that case was a much larger "sharkish thing" in the background with two outsized dorsal fins (strange), and a moving finless guppy-looking thing in the foreground. Too inchoate to be right, as I saw it. I redid my focus, and a discrete lone shark appeared; no extra fish. Like JES pointed out, it does indeed look like a bull shark.

It may help to see it if you look "into" the picture as if it has actual depth of space, like the interior of a box.

[DavidT]

Kewl! Never seen an animated one before.

[Redwolf]

Thanks for the tip! I've never been able to see these things, but I'd never thought about taking off my glasses and getting close enough to the picture that it's just plain easier NOT to try to focus.

Yep...definitely a shark.

Redwolf

[amar]

In general one says to relax one's eyes, and the picture will appear. What one actually does then is adjusting one's eyes as if you were focusing on something in the far distance, or, behind your actual monitor, thus diverging your eyes.

this never worked well for me.

I do it the other way around and it works each time for me:

I first look at the picture normally, one can usually tell that there are recurring lines, or little objects in the picture, these details are the ones that must be brought upon each other, either by diverging one's eyes, as I wrote above, or by converging one's eyes, looking cross-eyed.

So, check out where those duplicate lines are in the picture, then I slowly start crossing my eyes and concentrate on how the the two images from my left and right eye start to move apart. I concentrate on those duplicate lines (or other duplicate details) and cross my eyes to such an extent until the lines cover eachother. Then all you have to do is wait until your brain decides to see the new picture.
Easy.