Seeing three dimensions in two dimensions

Let me tell you right off the bat here that this isn’t an April Fool’s post. I promise you that.

I’ve just learned from The Observation Post that April is apparently ‘National Humor Month’*; this post isn’t meant to be funny. I promise you that, too.

I can already hear you asking: “Well, if this isn’t meant to be a jolly jape, what are you blithering on about, man?”.

I’ll tell you what I’m blithering on about: autostereograms.

Here’s one (click on image to embiggen):

Image credit: Gene Levine via Wikimedia Commons

It’s not a very exciting example, but there are no copyright restrictions on my using it here.

“But what is it?” I hear you say…

Well, this image has been created in such a way that if you unfocus your eyes in just the right way, you’ll be able to perceive it in three dimensions, not just the two it appears to be. Your best bet is to click on the image here so that you can see a larger copy of it. Just relax your eyes and try looking through the image. It may take you a few minutes before you get it.

You can tell if you’ve succeeded by moving your head from side to side; if you’ve got the right focus you’ll be able to see depth to the image.

As I mentioned, this isn’t exactly the most exciting example of an autostereogram. But there are loads of them on the web, just search for autostereogram. Some images are better than others: here’s a particularly good one by Scott Pakin.

You can get posters of autostereograms to hang on your wall to amaze your friends. I have a couple myself, one’s quite an impressive example, featuring an underwater scene — the way the shark leapt out at me the first time was quite an experience, let me tell you…

… and if you do think I’m pulling your leg, please let me know in the comments :)

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* Going by the u-less spelling of ‘humour’ I assume that the ‘nation’ in question is the USA.