Keywords: POP-I.A. learning to program, POP-II.A. novices, POP-III.A. variables, POP-III.D. visualisation, POP-V.B. case studies, POP-VI.D. computer science education research Abstract Many students learning to write computer programs encounter considerable difficulties. For novices, one of the key problems is in understanding how the very basic programming constructs work. In this paper, we
... [Show full abstract] concentrate on visualizing the role of a variable, i.e., the dynamic character of a variable embodied by the sequence of its successive values as related to other variables. We present a classification of roles and introduce an animation system, PlanAni, that uses this approach.