I was watching this edition of Click on BBC 24 the other day, and at the ten minute mark, there is a demonstration of Pyramid holograms.
Create your own
Pyramid Holograms can be made from the clear plastic cover of CD jewel cases. You will require one Stanley knife and a ruler.
Score around the edges and snap off the lipped edges, until you have a flat piece of perspex.
Use the template below, to create four sides.
Score the plastic gently to begin with, then apply more pressure. Will snap eventually.
Sand the sides to smooth sharp edges, after snapping.
Super glue the angled edges together, to form a pyramid. Use bluetack to hold the sides while gluing.
Sand the resulting flat apex if not totally flat.
Place the inverted pyramid on the iPhone screen, and play a video. Google for Pyramid Hologram Video.