The so-called “Trefolo” is the set of paths that connect the lecture halls. It consists of three twisting tubes with variations in height and plan. The three tubes (with a total length of about 100m) rest on irregularly spaced vertical elements (props and stairwell partition walls) with several significant spans. The project presented extremely challenging structural and technical challenges. Structurally, due to aspects in relation to its behavior under static and seismic conditions and, technically, due to the difficulty of site conditions during construction.