Herlev Hospital, on the outskirts of Copenhagen, is the tallest building in Denmark, and Poul Gernes’s complete interior decoration of that structure remains the largest painting in the country, perhaps in the world. Yet few of the patients who experience it may recognize it as art, for Gernes’s work is as resistant to categorization as it is eye-catching. Not only does his painterly world cut across the borders among Fluxus, Pop, Op, Minimalism, and Conceptual art, it also effaces the distinction between art and design. Gernes (1925–1996) championed the decorative, and insisted on popular access