A penthouse in Helmut Jahn's Streeterville tower, first designed for a German-American couple with a serious eye for contemporary art. When they returned years later to absorb more space, the challenge was expansion without disruption. A new media room with sliding steel and glass doors, a sun porch, and an enlarged kitchen and dining area joined the existing plan. Globally-sourced materials - Spanish marble, Italian tile, Chinese silk - extended the original textural language, while the cream lacquer millwork and curved walls that have defined the space from the start continued to hold it all together.