The Western tonal system is founded on specific procedures for modulating from one key to another; the harmonic relationships involved have parallels in Western architecture’s classic proportional relationships, suggesting the idea of architectural modulation.
In the above examples, the floor plan on the left shows the width-to-length ratios of the principal spaces in a project from I Quattro libri dell’architettura by Andrea Palladio (1508–1580). The unexpected and somewhat disturbing angled wall of the rear courtyard space could function like a pivot chord, leading to the hypothetical addition shown on the right.
This according to “Modulation in music and architecture” by Radoslav Zuk, an essay included in Systems research in the arts. IV: Music, environmental design, and the choreography of space (Windsor: International Institute for Advanced Studies in Systems Research and Cybernetics, 2003, pp. 1–8).