 CA are also being fruitfully used in connection to the issue of the thermodynamic limits of computation: is there a minimum amount of energy needed to perform a logical operation? Landauer (1961) argued that irreversible logical operations (i.e., operations that, not corresponding to bijections, cannot be run backwards as they entail some information loss) necessarily dissipate energy. The invention of the Fredkin reversible logical gate and of the Billiard Ball Model of reversible computation (Fredkin &amp; Toffoli 1982) strengthened the importance of the link between universal reversible automata and the physical properties of computation (for an overview, see Ilachinski 2001: 309–323; for a sample reversible CA, see Berto, Rossi, &amp; Tagliabue 2016).