As David explained, the effect is produced when there are varying degrees of alignment between two transparent layers each of which has a screen pattern. Same thing was seen on the Caesars Tahoe dollars. Don't try to collect them "all". There's an infinite variety.

Holograms provide a visual impression of a three dimensional image. As you move your head, you see differing views. A very few chips have been made with true holograms. Paulson did some with holographic center inlays. See one in the $100 chips in the ChipChat auction next month.