Tips for Viewing 3D Stereograms

1. Pick a spot on the picture (the middle seems to work best) and just stare at it.

2. Allow your eyes to relax, don't just stare AT the image, try to stare THROUGH it. You'll notice your eyes will go slightly out of focus. This is normal.

3. Keep staring, don't give up, once you begin to see the first image, it gets much easier.

More Explanations:
A hidden 3D image is what you can find in a stereogram if you know the proper way to look at it. When we look at something our eyes look at the same spot on a surface of an object. Our brain then calculates the distance to the object based on the positions our eyes have taken. But when we look a stereogram (the proper way) our eyes look at two different spots on the surface but the pattern on these two spots are the same, so our brain think that it is the same spot. Consequently our brain calculates a wrong distance and it seems to us that we are not looking AT the stereogram but instead that we are looking at something BEHIND the stereogram. That is how stereograms works.