Step3: Select beamball at time 1. You can see small beamball.
Step4: Move the slider to time 7. And choose Object-Velocity Control at menu-bar. You can see beamball grow. Velocity Control Panel shows that beam appears at 1 and disappears at 7.
Step5: Select beam at time 6. You can see the path of beam.
Step6: Move the slider to time 7. You can see beam appears.
Step7: Move the slider to time 8. And choose Object-Velocity Control at menu-bar. Velocity Control Panel shows that beam appears at 7 and disappears at 9.