Ask what-if questions spontaneously while working through a problem ... Easy / intuitive conveyance of information. Mathematically / algorithmically rigorous ...
Why Text is Tricky to Visualize ... 'How much is that doggy in the window? ... 'doggy' implies childlike, plaintive, probably cannot do the purchasing on their own ' ...
Interactive visual display of abstract information to help users: ... Visuals help us think. Provide a frame of reference, a temporary storage area ...