The selection of a building material was not always uncertain: In years gone by, the answer was almost always "steel." Steel was thought to be the material produced by Industry for buildings to be used and paid for by Industry. With the exception of the dome and the arch, building in Western civilization has been largely dominated by the straight line and the right angle.

Steel engineering, however, simply does not offer the perfect solution to our search for an industrialized system of design. Years ago, when the writer made a steel take-off for a high-rise building, he first became aware of the fussy character of steel engineering. What had been cleanly drawn on a clean sheet of paper as a set of uniform columns and beams became a jumble of different sizes and weights as structural steel members were selected for efficiency. The clean uniformity which had been achieved on paper had become a confusion of sizes, weights and lengths with a wide variety of connections. Fireproofing produced a further confrontation between the reality of codes and the abstractions of design. Worst of all, wind bracing was needed: The boxes of right angles now needed a hypotenuse.

Marina City in Chicago, designed in 1959, was the first major building for which we provided both flexibility for different kinds of people and industrialized economy for the bankers. We found that spatial forms for apartments, if designed in the interests of livability, economy and energy conservation, could no longer be boxes. The cylinder was a more efficient shape. We engineered the structure both in steel and in concrete to compare the costs. Concrete was less expensive by a substantial amount. Our first objective is to design a shape that will provide people with the best environment for the purpose of the building, and concrete has never failed us.