A discrete stack of diagrammatic precedent models generates a protobuilding. A connection between the stacked spaces through the alignment of a vertical corridor creates a centralizing programmatic approach and a double-layered building, or a building-within-a-building. Precedents include Reading Room at the Bibliothèque Nationale by Henri Labrouste, Vasconcelos Library by Alberto Kalach, and Sendai Mediathèque by Toyo Ito.