Stereograms!

I discovered stereograms around 2 years ago, and during these days, don't know why, I continued watching them. I had something like a backfire and now I can't stop looking at them! xD
Do you know what stereograms are? They look like normal pictures, but inside every image there's a second picture, an hidden one, that needs a "trick with the eyes" to be discovered. The best is, these hidden images are in 3D!!

I opened this thread to make something like a game: each of us post a stereogram they found on the Internet, and then the other users try to find the hidden image. I also found an online programme on DeviantART that allows to create any stereogram we want and use it! (http://3dimka.deviantart.com/art/Stereogram-Paint-74084936)
There are two kinds of stereograms: the first, which consists of two apparently-the-same pictures, and the trick is creating a third picture beetween the two, the same as the one we see but in 3D. The other one consists of a confused pattern that, if it's stared at in the correct way, gives an hidden image, and this kind is the one I'm talking about

These are some:
http://www.j3k0.net/blog/immagini/stereogrammi1.jpg
http://www.rivelazioni.com/stereogrammi/00-3.shtml
http://www.paolo-milano.it/Foto_stereogrammi_1/Stereogramma_000.jpg

And this is the easiest I found to begin with for those who don't know about stereograms yet ^^:
http://freegallery.no-ip.info/file183dim0qt0.jpg

Now for the trick: how to see them!
Stand around 30 cms from the screen. Then, imagine there's something behind the monitor, like a vase, or the wall, that must be at least 2-3 meters far from where you are. Now, imagine to see that thing from the computer screen. You have to "cross your eyes" imagining to see something in the distance through the pc monitor. It may take some time at the first try (it took me an hour! xD) but when you get the trick it requires some seconds.
If it still doesn't work, try placing a finger between you and the screen, and focus on that. Then, keeping the same focus, place your finger down and you should see all fuzzy, out of focus. Keep it, don't focus the screen... and there is the hidden image!
It it doesn't work either, continue practising... it can take more than an hour! >.<

We could make a game creating or searching for stereograms, and then trying to guess what they are! what do you think about it?^^

I have once seen this kind of thing in a film, I can't remember the name of it, in which all the members of a family playing a series of games as a kind of contest to see who's able to mark the highest score. And that is one of them. I played it with my classmates for only one time when I was a freshman (when the youth always likes to try something different), and, ALAS, it seems that I'm not born to acquire that kind of ability but that's interesting, for my answers are all imagined out.

ah, no, please no stereogramms!*joke*
I didn't ever get the 3d image (I have some sheets with stereogramms at home too), because I don't know how they're working *sniff*

It may seem hard to see them but it's actually simple. The trick is, you have to look at the stereograms as if you were looking at something farther through the desktop of the pc. Like, try to look at a wall, and then, without changing the eyes' focus, look at the screen. That's how I got to see them for the first time. ^^