 The idea of looking at logic as an entirety avoiding fragmentation is not new, and philosophers and logicians from Ramón Lull to Gottfried W. Leibniz have thought of building schemes where different logics or logic-like mechanisms could interact and cooperate instead of competing. In contemporary terms, the first methods for combining logics were products of logics (introduced by K. Segerberg (1973) and independently by V. Šehtman (1978)), fusion (introduced by R. Thomason (1984)) and fibring (introduced by D. Gabbay (1996a)), all of them dedicated to combining only modal logics. It is worth noting that M. Fitting (1969) gave early examples of fusion of modal logics, anticipating the notion of fusion.