from
Robins, Anthony, "The World Trade Center",
Omnigraphics, Inc. and Pineapple Press, Inc, 1987

(...) the tower windows, similar to the narrow windows in Yamasaki´s Michigan Gas Company Building in Detroit, were narrow for the same reasons. With floor to ceiling windows. Yamasaki felt comfortable only if the window width was narrower than his own shoulder span. According to the Roths, Yamasaki had a full-scale model of the window in his office, and by way of demonstration pushed Malcolm Levy into it; Levy´s shoulder stuck. (...)