utv_unstack_frame_stack
=======================

.. py:function:: t3toolbox.backend.utv_operations.utv_unstack_frame_stack(frame_data, variations_data)

   .. code-block:: python

      def utv_unstack_frame_stack(
              frame_data,       # frame .data,      supercore stack = C
              variations_data,  # variations .data, supercore stack = K + C
      ):  # -> array-like tree (shape C) of (frame_data, variations_data) pairs


   Peel the frame stack ``C`` off both the frame and the variations, returning a ``C``-shaped tree whose
   leaves are ``(frame_data, variations_data)`` pairs -- one single-base-point tangent per leaf.

   Each frame-``.data`` leaf has stack ``()`` (a single frame); each variations-``.data`` leaf has stack
   ``K``. The frame stack is the *inner* part of the ``K + C`` variation stack, so it is peeled from the
   interior axes ``1+|K| .. 1+|K|+|C|`` of the variation supercores; the frame's whole stack is ``C``. The
   leaves are paired for you (a plain :py:func:`stacking.tree_zip` would recurse into the data tuples).
   Inverse of :py:func:`utv_stack_frame_stack`.