A hanging roof was desired from the beginning, but this would require sloping roof mainstays that would take up valuable real estate and would make the building structure vulnerable to catastrophic failure due to accidents or vandalism. Through progressive designs, a method was developed, by structural engineer Wacław Zalewski, employing the principle of tensegrity, to eliminate the backstays by alternating cables and arches of similar curvature. The outward thrust of arches at their highest points exactly balances the inward pull of the cables at each end.
