d-isotropic grassmanian of k^[a+b] as mapping to d grassmanian of k^a .... ????? ...... ????? .....

g2 crown grassmanian .... "2d subspace of k^3, tw ... " ... ??? ....

?? 2d isotropic subspace of k^[3+4] ... rank 2 partial isometry from k^3 to k^4 ... ??? .... "rolling track" tw isometry ( ?? ... ) to "orientation" space ... ??? ...

?? paradox about maybe getting lower-dim than possible projective embedding of crown grassmanian ?? ....