From reading 'Bounce Tumble 'n' Splash' , a Blender Foundation book on the Physics Simultion elements of open-source Blender, I learned about using objects with particle systems, and tried out a few scenes, such as swarms of bees (that also uses the BOIDS system with particles - very cool!) swarms of flying musical notation figures, and finally, this... Which I decided to take a little further - and am still working on.