The Function of Systems Cities that once hosted nations now host a rich array of \'cosmopolitans\' as a result of processes of globalization. Cities are no longer singular \'wholes\' but molecular compositions that are differentiated and continually being redefined . Whereas the nation formerly provided cities with a singular ideal \'identity\', the cosmopolitan society that inhabits the contemporary city is made up of diverse and active constellations that co-habit the city in \'connected isolations\' (Sloterdijk). In place of a singular identity, cities need to provide different forms of expression that correspond to these different constellations. The molecular nature of cities, applied to buildings questions the way we relate parts to whole.What makes system appropriate today is their singular property of embracing multiple criteria and objectives at the same time given the complex nature of architectural problems and the molecular nature of the profession that divides this multiplicity into segments. Tessellation moves architectural experiments away from mechanistic notions of systems which are used as tools for re-production of forms, to machinic notions of systems that determine how diverse parts of an architectural problem interrelate, to multiply each other and produce organizations of higher degree of complexity. Unlike the simple repetition of part to whole in typology, or previous techniques based on frames, axes, proportions, or other discrete compositional instruments, tessellation allows for complex repetition through an aggregation of diverse parts. The complexity of this repetition is a function of the degree of correspondence inbuilt into the part-to-whole relationship.The seminar will seek to produce a graphic manual on tessellation. Continuing with the research last year, we will examine architectural projects that have a tessellated part-whole system, extracting their protogeometric base unit that is capable of proliferating different forms according to different circumstances. Related to this, the seminar will distinguish the uses of tessellation versus modulated geometries, and will therefore examine an extended list of projects involving both systems from various historical projects from the Medieval to the Modern with a major focus on Contemporary architectural production. . The seminar aims to bridge architectural research and production through drawing. While there will be ongoing reading and discussion on the topic and on the various case studies, graphic analytical production will be the main criteria on which grading is based.