The cloverleaf design Bertrand Goldberg used for Prentice Women's Hospital was groundbreaking back in 1975, when the distinctive concrete structure went up on Northwestern University's Streeterville campus. Supports for its four cylindrical towers were confined to the building's core, allowing for open floor plans, with patient rooms fanning out conveniently from centralized nursing stations. This year, Rush University Hospital opened a new medical center at Ashland and Harrison. Designed by Ralph Johnson of Perkins & Will, it's been drawing acclaim for its striking butterfly design featuring a curvaceous four-lobed tower, open floor plans, and patient rooms fanning out from centralized nursing stations. Northwestern moved Prentice out of Goldberg's towers in 2007 and has been sparring with preservationists ever since over its intention to tear them down. There's a "Save 'Old' Prentice" petition on the Internet; at press time it looked like a resolution might be imminent.