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
I have never ever in my life managed to make these work, I have no idea what's wrong with my eyes
you and me both. i can make the third dot appear, but the second i look away from it the effect is gone. and now my eyes hurt!
Normally it means you picked the wrong distance to the screen!
Tinker with that first - it might be much further or closer than you think, all depending on your screen and eyes.
Also, a hint: the central circle should stay straight in the middle, not closer to one or the other. At that point, below there will be three equally sized pictures, and then you can switch your sight to the central one.
Try using a bigger screen, or moving your screen further from your face. When moving your focus off the dot, move it to the closest part of the image and then move from there. It can help to align a feature in your periphery before moving to it.