Summary. Conflicting forms of particular freedom find a synthesis in the mosaic.
In system theory there are two fundamental principles: the local optimum of subsystems does not imply global optimum; the whole system is richer than the sum of its subsystems. It is what happens in the construction of a mosaic, where transcalarity implies that different form of freedom may arise at different levels. When different forms of liberty begin to be conflictual it is necessary to establish boundaries, that may be organic, but difficult to follow, or may be simplified, even if they are poorer of history. Some fuzzy cases are then considered, and some solutions are suggested. The last section is devoted to the analysis of some development trends, and is mostly founded upon Bak-Sneppen models, that seem to be particularly suitable for explaining the dynamics of urban renovation.
