I was reminded yesterday of some of Flight404's cool tests with setting up a 2D picture to have collision that looks correct in 3D dimensions.
The spheres were "whipped up" with the Kineme3D parametric surface patch.
I'm fairly happy the results of this as I experiment with it more! I think there's some pretty interesting results that can be had, especially with the introduction of the Quartz Crystal motion blur.
The nucleus of many of the principles used to achieve this in QC are present in the Particle Tools example compositions. The collision wasn't setup in any kind of automatic way; it is totally a manual perspective trick.
This was done in Snow Leopard, but doesn't make use of any Snow Leopard specific patches... and was put together while running the QC app in 32 bit.
Chris and Steve had nothing to do with vetting this posting, but it uses large parts of their example qtz's quite liberally, so it would be really wrong not to give credit. Steve's porting of Vee ala Particle Tools for QC has had some nice abilities to it, and Chris's parametric sphere, Kineme3D and parts of the Kineme3D/Particle Tools collider example where also used, though all of this has been highly tweaked and adapted to the scenario, and for the specific look I wanted.