Imperfect designs, perfect products.

• Position: Innovation

What do paper cups, toothbrushes, grocery bags, kitchen faucets, doorknobs, and automobile cup holders have in common? They all are the imperfect products of designers seeking to come up with something better for consumers. Henry Petroski, Aleksandar S. Vesic Professor of Civil Engineering at the Pratt School of Engineering, Duke University, Durham, N.C., looks at the design of things we take for granted and concludes there can never be an end to the quest for the perfect design.

In Small Things Considered, Petroski notes that all plans involve choice, usually to satisfy competing constraints, whether they be cost, size, efficiency, or the myriad other factors that make the difference between a design that works and one that doesn't."... The design of made things, as opposed to design in nature and the artistic interpretation of it, necessarily proceed within the confines of the laws of science and economics. An ... inventor or designer of practical things must accept the realities of gravity and budgets, keeping his feet on the ground and his eye on the price."

Petroski examines a variety of common objects and how their designs evolved. Take the paper cup for example, which was spawned early last century when people began to realize that the communal tin cup from which everyone--healthy and sick alike--drank at the...