module type Synchronism =A synchronism defines when and where the rule is applied; they are implemented in folder rule, like the simplesig..end
Synchronism.Synchronous.val next_step : ('a array -> int -> 'a) -> 'a array -> 'a array -> unitnext_step transition_rule configuration_in configuration_out
    doesn't modify configuration_in and writes the updated configuration in
    configuration_out.