In Shape, George Stiny argues that seeing shapes-with all their changeability and ambiguity-is an inexhaustible source of creative ideas. Understanding shapes, he says, is a useful way to understand what is possible in design.

Shapes are devices for visual expression just as symbols are devices for verbal expression. Stiny develops a unified scheme that includes both visual expression with shapes and verbal expression with signs. The relationships-and equivalencies- between the two kinds of expressive devices make design comparable to other professional practices that rely more on verbal than visual expression. Design uses shapes while business, engineering, law, mathematics, and philosophy turn mainly to symbols, but the difference, says Stiny, isn't categorical. Designing is a way of thinking. Designing, Stiny argues, is calculating with shapes, calculating without equations and numbers but still according to rules. Stiny shows that the mechanical process of calculation is actually a creative process when you calculate with shapes-when you can reason with your eyes, when you learn to see instead of count.