animateMotion
Two circles are moved along a quadratic path with
a duration of 30s and repetition.
A closed path is given with the mpath element.
The rotate attribute is auto, this means for this
animation the circle group is rotated once for
one repetition. The small light blue circle is oriented
relative to the large blue circle in motion direction.
Normally the light blue circle is not exactly centered
below the path, but close to it.