4/11    I have 2 normalized 4D vectors v1 and v2 which are linearly independant
        How do I find a length and angle preserving (forgot the terminology)
        transformation which maps the vector v1 onto v2?  I know the Rodrigues
        rotation formula for 3D but that doesn't seem to apply.  I looked at
        http://en.wikipedia.org/wiki/SO(4 but most of it went over my head.
        \_ Most of this post went over my head.
        \_ If you are talking about projection of v1 onto v2, the forumula
           would be ((v1 . v2) / (v2 . v2) )*v2.  If this isn't what you are
           looking for please clarify,  Also, this has no dependance on the
           vectors being normalized.
           \_ No I don't mean projection.  And I know how to use the Graham-
              Schmidt process to find basis vectors for the nullspace.  What
              I am looking for is a matrix which is an isometric transform from
              v1 to v2.