My time has come!
The above stereographic image is for cross-eyed viewing (most stereograms are wall-eyed, so you may need to put your finger in front of your screen until this one comes into focus)
This is an image of Honolulu, Hawaii, published by NASA. Note Diamond Head (the volcanic crater) in the south.
Here are some other stereopairs published by JPL:
Wheeler Ridge, California
Mount Saint Helens
Salt Lake Valley, Utah
Wellington, New Zealand
Really can’t seem to understand how this works.
Never did any “magic eyes” or whatever books as a kid, so maybe I just don’t have any practice in this, but whether I try to cross my eyes focusing beyond the screen, or “above” the screen, I can’t get the resulting middle image to look like anything other than a blur.
Perhaps my eyes are somehow odd on the other hand. I don’t need glasses though, so I’m a bit skeptical that’s it.
I tried all the guides I found in this thread, including the floating hot dogs, attempting varying distances both with the screen and the finger, then trying the wall-eyed variants too for all of them, none of them work for me.
So odd. It seems it should work. No idea what I am doing wrong here.
Or is this the joke? To get people to squint for minutes on end on their screen?
I was gonna tell you it was a meme and they don't actually work. This being in science meme I thought they might actually be stereographic images, but it's from so far away you wouldn't be able to discern any 3D-ness. But I was wrong the height is exaggerated. For me the walleyed version worked for me, I just had to zoom in on one image and hold my phone quite far away.
They do work. It takes some practice to get them though. At first I used a pencil or something to focus on while I made the two dots merge together, stayed focussed on the pencil until my brain "saw" the image behind it, then it sort of locked in and I could take the pencil away. I've done so many of them now that I can just go crosseyed to bring the dots together, then look at the middle picture.
The 3D image works by tricking your brain into seeing a third image that isn't really there. We're used to constructing 3D images from two slightly different views; we do it all the time, so the two images are slightly different and when overlaid use the same mechanism to make you think it's 3D.
I used to be able to do them at will, and even overlap images an additional time to get a crazy second level of shape.
But now I can’t, thanks to the american health insurance industry. yay!
I promise this isn't a troll. In your case, it may be that your eyes are having difficulty focusing on nonexistent objects. If they're blurry, it's not that your eyes aren't crossing, but rather that they are out-of-focus. Eyes naturally focus the lenses to bring near or distant objects into clarity, but when I was first doing magic eye images a long time ago, it also took me a while to convince my eyes that they needed to focus on the images.
My guess is that, since the actual images are on the screen at distance A, but your eyes are crossing as if they're looking at distance B, your eyes are auto-focusing for objects at B, but the images are still actually at A, so they appear out-of-focus.