A sensing device for sensing region identity data and generating movement
data when the sensing device is moved relative to a region of a surface,
the region identity data being indicative of an identity of the region,
the movement data being indicative of the movement of the sensing device
relative to the region, the surface having disposed upon it coded data
indicative of at least one region associated with the surface, the
sensing device including: region identity sensing means configured to
sense the region identity data using at least some of the coded data;
motion sensing means configured to generate the movement data; and
communications means configured to communicate the region identity data
and the movement data to a computer system.