Sometimes it is necessary to study the most general rule possible,
given the neighborhood and state set, making it necessary to present
the full rule for editing; the most compact way to do this is to show
two 
matrices, again differentiating them by the central
cell to which they refer.
The circumstances under which a really general rule has to be defined are often that a given course of evolution is being sought. So the editor for such a rule ought to incorporate provisions for trial evolutions; also for marking portions of the rule which have already been settled upon to distinguish them from those yet to be decided. Finally, the rule ought to be saved somehow, if tedious manual transcription, or laborious repetition at a later date, is to be avoided.