1. A method, comprising: forming a first image that encodes information indicative of a map relating at least one pixel pattern to at least one function implemented by a processor-based device, wherein the first image is formed so that the processor-based device can decode said information to generate the map; and forming a second image that comprises said at least one pixel pattern, wherein the second image is formed so that the processor-based device can detect said at least one pixel pattern using the map and implement said at least one function.