How to implement affine transform stack

I think SetWorldTransform/GetWorldTransform/ModifyWorldTransform are the
functions I want. Does anyone have an example that implements a stack?

(1) I want to call SetWorldTransform in MM_ANISOTROPIC (why does not this
work?)

(2) Draw some rectangles.
(3) Call ModifyWorldTransfom to draw more rectangles inside the last
rectangle where the origin is now the upper left corner of the last rectangle.
(4) repeat step 3.
(5) Pop my stack back to the original origin.

How would I do this? Anyone got an example? Would I push a copy the entire
current transformation matrix on to a stack? I would I just push the changes
on to the stack and when I pop, compute the inverse matrix (ugh...) and
multiply that by the current matrix (ugh...) to get the original matrix...

Anyone got an example?

Thanks!
Siegfried