When I first viewed stereograms back in the 90's, I was amazed by how the eyes could be tricked into seeing a 3D image without the use of filters to direct different images to each eye. After studying the problem for a while I figured out that it was not really all that difficult to produce some of the effects. Here is one of the first stereogram images I ever created. I used small versions of my computer-generated snowflakes placed to give the illusion of three bigger ones. For viewing tips on stereograms go to: