 In the early Sixties, E.F. Moore (1962) and Myhill (1963) proved the Garden-of-Eden theorems stating conditions for the existence of so-called Gardens of Eden, i.e., patterns that cannot appear on the lattice of a CA except as initial conditions. Gustav Hedlund (1969) investigated cellular automata within the framework of symbolic dynamics. In 1970 the mathematician John Conway introduced his aforementioned Life game (Berkelamp, Conway, &amp; Guy 1982), arguably the most popular automaton ever, and one of the simplest computational models ever proved to be a universal computer. In 1977, Tommaso Toffoli used cellular automata to directly model physical laws, laying the foundations for the study of reversible CA (Toffoli 1977).