Minor vs. Dorian

The first of these is the natural minor scale - Aeolian, in Greek-mode terms - and both start on C.

The wheel makes the difference positional rather than verbal: the sixth-degree wedge sits one wedge further clockwise in Dorian, and the spoke drawn from the center recolors to the interval that degree now forms with the tonic. Everything else on the two wheels is identical.

That single degree is why Dorian is the brighter minor - it is the scale that keeps a minor third but refuses the minor sixth. Reading it is one thing; the difference is much more obvious held under a drone, which is what the links under each figure are for.