is the "rolling and/or spinning" distribution on the g2 "point" grassmanian the zariski tangent space of any schubert variety?? of course since it's defined in terms of lie bracket from the pure rolling distribution, it has a sort of "geometric interpretation" in terms of nelson's "parallel parking" metaphor, but does it have some sort of more direct "incidence geometry" interpretation?? not sure exactly what i think the rules should be here as to what qualifies as such an interpretation...

this is part of the larger question of relationships between schubert varieties (possibly generalized in certain ways) and invariant distributions in general...