An architect's goal is to design appropriately for the time. In the mid-to-late 20th century postmodernists such as Venturi found modernism's purism and oversimplification lacking. Venturi recognized that the world is not simple in nature, but full of complexity and contradictions. Postmodernists aim for an implicit richness of meaning through complexity and contradiction rather than an overt oversimplified clarity of meaning. A building is basically composed of a variety of paradoxes, such as external and internal spaces, primary spaces and secondary spaces and so on. In Complexity and Contradiction in Architecture, Robert Venturi states that “overt simplification means bland architecture” and elaborates on the need for architecturally appropriate complexity and contradiction for modernity (Venturi, 25). "A valid order accommodates the circumstantial contradictions of a complex reality" (Venturi, 46). According to Kahn, “it is the job of design to adapt to circumstances,” however, modern architecture has “operated too long under the restrictions of an inflexible rectangle”....