In switching-off a light, one has “saved” a quite large lump of Coal
( I your adminstrative-publisher, often utter
the ‘alternative-sense-wording “Coal Off !” ).

“Coal on” is sometimes an essential –  provided “Coal off” has the Dominant Regulatory Power.


Now, punctuation-wise, the “colon” is not only essential but “Existential” too – because there is no such punctuation as a “coloff”,

So “coloff” is Non-existential
[NB one durst not say “it is non-existent” because mentally it does ‘exist’ – ]

a further factor that

on the ground “coal” not only does “exist” but is in dire need of both “conserving” and “preserving”;
i.e. is in need of being made “more existential”

============= 1754  we break for a chores-bottleneck, and for self-catch-up & maintenance, life-work-and-rest ===============..