So I have understood the "points" of one solid surface, and the area drawn by these points.

After others tests I understand, that "Flow" consider as "Base", any circular form, like a square (or rectangle).
So it's why, it must to take a solid/Plane for Base of the objets to deform; & not to want absolutely to use a circle; because a solid/square gives the same result.

So, to deform a single torus on a sphere or on any part of one sphere, that give results; but not the one that we would.

We cannot to curve or to round off, a simple torus, like a piece of a round shield bulging (domed, rounded).

If someboby arrives to do that with "Flow", that means that I have understood nothing.

I would like to be wrong! Because I round often objets on a spheric piece.