A printed media product, such as a trading card, that has a substrate and an encoded data element applied to a surface of the substrate containing information. The encoded data element includes first, second, and third data layers with first, second, and third patterns of encoded, colored dots defined...http://www.google.de/patents/US20040246529?utm_source=gb-gplus-sharePatent US20040246529 - Printed media products including data files provided in multiple layers of encoded, colored dots
