 Therefore, by the Curtis–Hedlund–Lyndon theorem, the time-reversed dynamics of the cellular automaton may itself be generated using a different cellular automaton rule.However, the neighborhood of a cell in the reverse automaton may be significantly larger than the neighborhood of the same cell in the forward automaton.One can generalize the definition of cellular automaton to those maps that are defined by rules for computing the new value of each position in a configuration based on the values of cells in a finite but variable neighborhood surrounding the position.