Teaching a Mouse How to Draw

An apprenticeship metaphor is described for programming by example, graphically, which enables untrained end users to add composite operations to a drawing program using constructive methods traditionally employed in drafting. To combat the extraneous activity that plagues naturally-produced traces, interaction is used to constrain induction by suppressing, or at least controlling, variability . A device called "Metamouse" serves to concentrate the user's attention on the system's limited inferential capabilities. It predicts actions, asks for constructions, solicits input parameters when required, and induces a program. Implications for machine learning include the benefits of simulating a pupil to complete the teaching metaphor, and the role of user interaction in constraining the search for apt generalizations . Implications for computer graphics include the feasibility of teaching an interactive editor to perfonn repetitive graphical procedures and the use of familiar drawing primitives as a basis for more complex transfonnations.