a slightly optical illusion, just view relaxed and be patient, your eyes need a moment to realise the 3D or holograhic effect… (best viewed zoomed and a bit more far from the monitor as usual – round about. 3 feet/1 Meter distance)
The distance how far to be away from the monitor is variable and differs from person to person. If you look not to “concentrated” (a bit blurry) than the coloured area should step into the background while the small blue element of the image step a bit in front. It than seems that there are these two layers with a distance of some millimeter (1/4 inch).
If you now move your head to the far left side and then slowly back to the far right side the blue element seems to be following you while the background keep fixed.