Key by Key on C6 Pedal Steel

A key is not a mood here, it is a lookup. Somebody calls one at the session, the seven plain numbers resolve to seven named chords, and a different call resolves the same seven digits to seven different chords with nothing rewritten in between.

The three degrees that carry a mark are the same three in every key, which is the fact that makes the whole grid memorable rather than a table to be looked up.