A sensing device for generating orientation data when positioned or moved relative to a surface, the orientation data being indicative of an orientation of the sensing device relative to the surface, the surface having coded data disposed upon it, the coded data being indicative, when sensed by the sensing device, of the orientation, the sensing device including: a housing; orientation sensing means configured to generate the orientation data using at least some of the coded data; and communications means configured to communicate the orientation data to a computer system.