I have no idea how that is supposed to work. If I cross my eyes I see 3 images and the middle one is a superposition of the two but I don't see any part standing out.
It's subtle. You need to make sure the center image is very well in focus first. Then, the "shimmer" appears but it's not really a shimmer so much as a (fairly mild) perceived depth/edge "artifact". It seems to glow but i think this is more to do with it looking a bit like glowy edge based artifacts from 3d movies w/ 3d glasses.
