Hi @Stanley
This is quite easy in Bongo, which is an animation plug-in for Rhino. In vanilla Rhino, no object animation is possible, only really simple camera animations - although it would be possible in Grashopper as well.
HTH, Jakob
Perhaps I will try to learn how to do this in Grasshopper, since I already have it with Rhino 6.
Maybe Bongo would be good and easy to use, but acquiring it would cost me extra money. Moreover, I am always a little wary of plug-ins, because they might cause trouble with the main program.
Anyway, thank you for pointing me in useful directions.