The Netherlands has issued a lenticular video stamp, using a special printing process on a stamp-sized piece of plastic. Each stamp sells for .39 (46 cents US), and before you think that's crazy, keep in mind that these are not flat panel displays that we're talking about. How does this work, you might ask? The technique is a variation on those little plastic decoder rings you might have seen as a kid—as you tilt the stamp to the left and right, the series of images appear to play back in sequence. Here's how Outer Aspect, the company that printed these video stamps, explains it:
Lenticular is a specialised printing process that can show depth, motion, HD video, film or combinations of these. The lenticular material is made up of tiny ridges or lenses (hence the name "lenticular" printing). We take raw images and process them through a computer algorithm, which matches the lens surface of the lenticular material. When the two work together it enables the image to be replayed back to you. The printing is always on the reverse side of the Lenticular lens material, as this is where the focal point is, allowing the images to be replayed back to the human eye as the viewing angle changes.
This technology can also be used for 3D graphics and lots of other jaw-dropping stuff.
How It Works [Outer Aspect, via PicturePhoning]