h.. toggle CELL-semi-frozen or SEMI-frozen-cell or FROZEN-cell-semi
This option allows ``frozen cells``, that have not changed over the last x time-steps, to be highlighted. The initial default is x=20, but this can be reset (see below). Key ``h'' toggles between the following
CELL cell colors by value.
SEMI frozen cells colored green, the rest by value.
FROZEN frozen cells colored green, the rest the background color.
H.. generations (now 20) (to change default number of generations defined as frozen above)
The default number of generations (or time-steps) for a cell to be considered ``frozen'' may be reset. If key ``H'' is hit, the following top right prompt appears,
enter new 'frozen' generation size (now 20):
Enter the new size which becomes the default.