begin list and restart
The animation of cy of a circle with a duration of
4s is started with a begin list at 1s and 5s with a
restart whenNotActive. Due to the end exclusive
SMIL timing model the first turn is not active
at 5s and therefore the second begin can be started.
An animation of the cx gives the timing, the resulting
motion is indicated by a grey path covering the red fill
of the circle. If the circle does not move along the path
or the red center gets visible, an error is occured.