Moving Objects Symmetrically with a Fulcrum-selected Mirror Plane
Example:
Pivoting an edge modifies the matching geometry on the other side of the
fulcrum-selected mirror plane.

Moving faces that are symmetric to each other but lie partially on either side
of the mirror plane. The center of each of the objects' bounding boxes is on
either side of the plane, so the symmetric move tool can detect the symmetric
geometry and the angled faces can be moved.
