playbackOrder example
For two circles the radius is animated from
zero to large to zero in 10s. The blue
circle covers always the red circle.
The red circle is discarded at 7s using the
discard element, the display of the blue
circle is set to none at 7s.
The animation of the radius of the blue circle can be
restarted clicking the small blue stroke circle bottom right.
The restart is realised with a back seeking hyperlink to
a fragment identifier. Because playbackOrder is set to
forwardOnly the red circle keeps discarded.
If the red circle gets visible at any time, an error occured.