On: What chords do you need?

[felix318]

Technically any sequence of notes within the octave is a scale, including the chromatic scale (111111111111). The French composer Olivier Messiaen did some investigation into how many scales can be built, I think the number is a bit over 800. Of course most scales sound weird to unaccostumed ears.

[bazeblackwood → felix318]

And that’s just within 12 tone systems! Scales don’t have to repeat over the octave, see Wendy Carlos’ work in this area.