These were placed along the walls of the service core, the central blob of elevators and toilets. It was the Hancock's only stroke of luck. Nobody was to blame. The Hancock met every structural building code. So it was necessary to stiffen not only the tower but also the codes, and that was done.
Nobody knows, but nobody was willing to take the risk.
A very few panes of the new glass have failed, but that's normal. After all the testing it went through, the Hancock today has got to be one of the safest high-rises in the world. It possesses the strength of a survivor. So does its architect. Harry Cobb went on to become chairman of the department of architecture at Harvard and is currently the designer of a new federal courthouse on Boston's Fan Pier.