The book reflects the narrative structure of the exhibition: looking at fragments and moldings as the occasion in which ornament is discrete and condensed into few precise points; considering columns as ambivalent structural elements; looking at cladding as a conscious project rather than the passive result; exploring patterns, intended as regularly repetitive arrangements reflecting the time and the society in which they are conceived; looking at information superstructures like texts, frescoes and screens, when they become the main instrument to compose a building; enlarging ornament to the whole urban environment, embracing the complexity of shared space and imagining it as a scene for the development of public life. This is the fourth volumen of a five book series for the fith edition of Lisbon Architecture Triennale. A unique and limited collection edited by the curatorial team of The Poetics of Reason: a sparkling intellectual reflection from a three-year investigation on architectural rationality.