Some of you may already have came across 3d steriogram images some time, but thought its an interesting thing and for some members it may be new.
Stereograms are 3D images hidden within another picture. A stereogram is an optical illusion of depth created from flat, two-dimensional image or images. Originally, stereogram referred to a pair of stereo images which could be viewed using stereoscope. Other types of stereograms include anaglyphs and autostereograms.
Tips on Viewing the images :
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.
(tips text taken from http://www.eyetricks.com/3dstereo.htm which also contain of images collection)
Few links to images :
http://www.eyetricks.com/3dstereo20.htm ( Horse )
http://www.eyetricks.com/3dstereo32.htm ( Flower )
http://www.eyetricks.com/3dstereo80.htm ( Brick Bits )
Many other you can find on this site and in general on internet.
And don't get frustrated if you are not able to view the 3d image