Sorry, the notes were supposed to line up. Should have remembered that spaces are "pulled together".

There are lots of interesting (and sometimes amazing) chord "synonyms". An easy pair is vi min 7 == I 6, e.g., A min 7 == C 6 == A C E G. Am is, of course, the relative minor of C and is the sixth interval in the C major scale, so I write I and vi. I do actually write this a lot; on sheet music that I want to transpose. For example, the diatonic chords for the major scale can be written like this:

I maj 7 --- ii min 7 --- iii min 7 --- IV maj 7 --- V 7 --- vi min 7 --- vii min 7 b5 --- I maj 7

It is very worthwhile knowing this by heart, so that one can rattle it off without thinking, as well as the circle of fourths and circle of fifths. And I am not one who goes in for learning things by heart without good reason.

I use some symbols that aren't on the keyboard and wouldn't be displayed properly everywhere, anyway, such as a triangle for the maj. 7th, a circle with a diagonal through it for the min 7 b5, etc.