1. Apparatus for controlling an interactive display device, comprising; a surface on to which an image produced by a processor means may be projected, said surface comprising an optically discernable pattern or ornament, said pattern or ornament having encoded characteristics capable of providing unique positional reference information and/or control information in respect of positions on said surface; a sensor means, said sensor means being configured to capture said unique positional reference and/or control information relating to its position in relation to said optically discernable pattern or ornament on said surface, and to transmit said respective positional reference information to a processor means; a processor means, said processor means being operable to receive said positional reference and/or control information from said sensor means; said processor means being operable to associate said positional reference and/or control information with functions relating to at least one computer program operable in said processor means.