Aqua Tower Ripples in Chicago

Aqua Tower in downtown Chicago uses a rectilinear plan in its reinforced concrete structure, with hotel, rental apartments and condominiums, as well as penthouses on the top two floors. The architect figured out the envelope's curvilinear architectonic forms while working with the building’s rectangular footprint. At the same time, she devised ways it could be energy efficient through sustainable strategies, using passive solar principles. http://www.solaripedia.com/13/188/rippling_tower_undulates_in_chicago.html