animation and constrained transformations
transform ref(svg) is applied to a centered blue rectangle.
The rectangle is nested in three g elements, one of them
is animated with skewX with some nasty values,
one with rotate and one with some nasty scale values.
All these animateTranform has no effect on the blue
rectangle, covering all the time completely the
red reference rectangle.
For comparsion there is a gray stroked rectangle on top without
transform ref(svg) and with vector-effect non-scaling-stroke
indicating the current transformations.
The center is marked with a gray rectangle. If something red
gets visible, maybe the attribute is ignored.
If the gray rectangle is not visible, this is an error
too. If the viewer crashes, presumably it tries to
calculate the inverse of a matrix without an inverse.