Revisiting the phenomenon of synesthesia between the arts that had already been explored in the House for a sculptor, the “Urban nodes” (1962-1966) are the earliest examples of a series of systems he designed for inserting sculpture into the city, among which are Brancusi’s Endless Column, Lucio Fontana’s Natura and projects inspired by the sculptors Azuma, Marchese and Benevelli. The different drawings in the series illustrate structures with both elementary and more complex forms, emerging from a deteriorated or chaotic urban fabric without quality. Imposing and spectacular, turned toward a monotonous environment which they contradict with their sculptural forms, these structures disturb and blur traditional architectural bearings: façade, floors, front/back, etc. This is reflected by the group of three conical structures, or the truncated hemispherical form from which underground galleries seem to fan out. As La Pietra explains, these nodes break with the formal systematic planning process, and, as moments and spaces of rupture, they tend to restore a semantic to the city, by fostering a new vision of the structure of the places where one lives, of the deep relationship woven between individuals and their environment.