Autostereograms trick the eye by using a repeating horizontal series of random dots. Because of the repeating nature of the autostereogram, you can not only focus on the dots directly but also on one of the other repeating series. What makes it cool is that the series of random dots can be shifted slightly to simulate depth. This is similar to how a ViewMaster and other stereo photo viewers work, where a slight difference in images can simulate an object as being closer or further away. A computer is required to generate an autostereogram since each dot must be calculated. With our ePaper display, that means there are over 46,000 dots, or pixels that must be calculated.
The animation below shows how the pixels move when creating an autostereogram of a square. The repeating series is shifted to make it appear the square is in front of the background. It is also interesting to note that although the moving pixels are on the right side of the image, the 3D image is centered since the stationary pixels are combined with the moved pixels to create the 3D image.
You can find a more detailed explanation on how autostereograms work and their history from this Wikipedia page.