There is provided a method of, and interface system for, enabling a user to instruct a computer system to perform an operation by interacting with graphical information and coded data printed on a first interface surface using a sensing device which generates indicating data indicative of the operation...http://www.google.com/patents/US7969425?utm_source=gb-gplus-sharePatent US7969425 - Method and system for enabling user instruction through interaction with interface surface
