Remember those little plastic things - or eyes on fake glasses that have little plastic ridges on them , and as you tilt them, they show a different image? Well, the technology has grown up - with up to 200 fine lens ridges per inch - allowing three images to be precisely superimposed showing different layered images or data in the same space. This example is a map of Manhattan that magically shows a street map, neighborhood areas, and attractions, flipping views as you tilt it a few degrees.