Patent ID: 7287688

Claim:
A method of enabling a user to instruct a computer system to perform an operation via: an interface surface including an interface, the interface including visible graphical information and substantially invisible coded data; and a sensing device which, when placed by the user into an operative position relative to the interface surface to designate at least some of the graphical information, senses at least some of the coded data and generates indicating data indicative of the operation using the sensed coded data; the method including the steps of, in the computer system: receiving the indicating data from the sensing device; performing the operation indicated by the indicating data; and controlling a printer to print a second interface surface in response to performing the operation, wherein the second interface surface is printed with visible graphical information relating to the performed operation and substantially invisible coded data; wherein the graphical information designated by the user is at least partially indicative, to the user, of the operation, and wherein the sensing device is further adapted to store a sensing device identifier which is adapted to distinguish the sensing device from other sensing devices of the same type.