>I assumed, when creating the posting, that my audience could visualize
>tangent lines to curves and tangent planes to spheres/surfaces [NOT
>compute them!], and that the concept of right angles and distance were
>reasonable. The above IS sufficient to understand "orthonormal frames
I too found your explanation of orthonormal frames incomprehensible.
I have no trouble imagining tangent lines to curves and tangent planes
to surfaces, but these weren't mentioned in your explanation (at least
not in way I recognized).
-- David McFadzean david@lucifer.com Memetic Engineer http://www.lucifer.com/~david/ Church of Virus http://www.lucifer.com/virus/