book on the Campo Marzio
...an analysis of five or six complexes that basically consist of large circle formations. There is a large middle area of the Ichnographia where one can discuss a half dozen large round complexes. I call them a profusion of bubbles.
The circle-squared diagrammatic plan formation of the Porticus Neronianae compared to the earlier plan of Palladio's Villa Rotunda and to later designs by Louis I. Kahn.