About Bullet Physics: Back in July of 2013, Bill Pragnell posted some 'falling
rocks' animations that he created. Not much info as to how it was done, but the
animations look great:
https://news.povray.org/povray.binaries.animations/thread/%3Cweb.51dc6d40c6eb1333354ba950%40news.povray.org%3E/
