I've had PI for about a month and have been working my tail off to get good at it. One effect that I have had only modest success with is taking a single particle (such as a circular picture) and rotating it around the center axis smoothly. The best I have done so far is to use a small number of particles which flicker somewhat, speed up and slow down.
Of course, PI is not intended as a basic animation product, but it seemed to me that it should be easily capable of simple moves such as this. Am I wrong?