In Rome Unit 15 may exploit a Reverse Borromini, a Baroque hyperspatial architectural stratagem that is usually one ploy in an elaborate sequence of architectonic moves used to gain space and time. According to Anthony Blunt 'Borromini began with a simple plan and gradually elaborated it by introducing variations, replacing straight lines with curves, and then making those curves more complex till the final refinement of movement and space was attained. We can trace his steps along this path in his designs for S. Carlo (alle Quattro Fontane) and the Palazzo Carpegna ...and we can be fairly sure that in cases where the early stages of the design are not recorded he followed the same process of thought.' (Blunt, 1979: 22)** Subsequently the Reverse Borromini was refined and embellished upon by Syd King and it's now thought that his most fantastical variations were enacted at Boleyn Castle.
** Blunt, A. (1979) Borromini, London: Allen Lane. Available in Avery Hill Library.