A method of enabling user interaction uses an interface surface which
contains information relating to at least one drawing field. The
interface surface includes coded data that is indicative of an identity
of the interface and a plurality of reference points. A sensing device is
provided which senses coded data when placed in an operative position
relative to the interface surface, and uses this to generate indicating
data indicative of the drawing field and data indicative of the sensing
device's movement or position relative to the interface surface. The
method includes having a computer system receive the data from the
sensing device and use this to identify the drawing field and any
movement of the sensing device within the field.