Mat-building is a low-rise, high-density construction which characterizes European architecture of the 1960s and 1970s. The term is coined by Alison Smithson and its paradigm is the Free University in Berlin by Candilis, Josic, and Woods. Based on a strong internal order and indeterminacy in form, mat-buildings’ design is a combinatory method. In Spain, Rafael Leoz and Ricardo Bofill demonstrate the utility of this way of designing to conceive high-rise works. This paper addresses how these proposals anticipate some important aspects of contemporary architecture.