A method and system for enabling user interaction with computer software running in a computer system via an interface surface and a sensing device. The interface surface contains information relating to the computer software and coded data indicative of a drawing field. When placed in an operative position relative to the interface surface, the sensing device senses indicating data indicative of the drawing field and generates movement data indicative of the sensing device's movement relative to the interface surface. The indicating and movement data are received in the computer system from the sensing device. The drawing field is identified and then the computer software is operated at least partly in reliance on the movement data, and in accordance with instructions associated with the drawing field.