The PositionInterpolator is used to generate translation values for the ball. The keyValues increase to (0.6 0.6 0.6) and then go back down to (0 0 0). Thus during the animation cycle the ball will move back and forth. Another interesting feature is that the ball speed varies. In the first and last time slices (0, 0.25), (0.75,1) the coordinates change by only 0.2 whereas in the middle two timeslices the coordinates change by 0.4. Thus the ball is faster in these middle time slices.