For k<=5, if if ``3'' is entered above the rule number is decreased by 1 at each mutation (if ``5`` is entered, the totalistic code number is decreased by 1). For a rule or code mix (or neighbourhood mix), each rule or code in the network is decreased by 1, after reaching 0 the rule or code number restarts at its maximum value. For a homogenous rule network, when the rule or code reaches 0 the mutation sequence stops.