Joshua Heineman - Stereogranimator

Like is often the case, it was dumb luck that changed my private interest into a years-long art project that captivated the Internet (as much as such a thing can happen) & made this NYPL application possible.
One evening in my final year of college, I was downloading digital snapshots to my laptop when I got a fleeting sense of 3D as the preview screen flicked quickly between two similar shots. I located the individual photos & flipped back & forth between them continually. The parallax effect of minor changes between the two perspectives created a sustained sense of dimension that approximated the effect of stereo viewing. When I realized how the effect was working, I set about discovering if I could capture the same illusion by layering both sides of an old stereograph in Photoshop & displaying the result as an animated gif. The effect was more jarring than through a stereoscope but no less magic
source: Joshua Heineman - Stereogranimator