We're near the end now. Faced with such a multiplicity of problems, the architect, Harry Cobb, decided he needed some ultimate reassurance that his building was safe. Thurlimann's discovery is the most astonishing of all these events. He announced that, according to his calculations, under certain rare but entirely possible wind conditions, the Hancock might fall over. Most amazing of all, it would fall on its narrow edge.
Nobody ever thinks of a long thin building like the Hancock falling over in the long direction.
The building was stiff enough in the flat direction. The danger was that it might collapse on a narrow edge. It would be as if a book standing upright on a table were to fall on its spine. If it shifted out of plumb by even a tiny bit in the long direction, the force of gravity, acting over such a great length, would begin to pull it farther. With each period it would move a little farther, until it fell.