I don't think the shapes themselves are meaningful, they just picked a bunch of different ones to represent different chordal elements; but the rate at which the ET ones move is supposed to match the difference beats, I think. The difference beats didn't sound as obnoxious to me as the keyboard tone itself did in both tunings :)
I take it this Justonic is software that corrects intervals and chords of input music based on some kind of JI coding. Now, they played a bluesy bit towards the end of that video--which implies that there are standard just ratios for blue notes, at least for purposes of that software's algorithm. This is something I've been wondering about for a while.
If a perfect minor third is 6:5, and a perfect major third is 5:4, then what would a "perfect" blue third be? 11:9?
