Modern architecture is not, from a lexical point of view, uniquely definable. The heterogeneity of the twentieth-century heritage is therefore a collective wealth that should be protected from the risk of falling into oblivion. In order to avoid this, it could prove fundamental to establish a process of the knowledge of these assets. This should not, however, result in a simple and passive recording of architectural facts: a deep understanding of the complexity of modern architecture, which has as its objective the protection of buildings, could be obtained, for example, through real and proper decoding of signs, conducted by a critical use of the metalanguage most congenial to the architect: the drawing. This is what was attempted with Lui...