[Al Skierkiewicz]

Chris,
I am not sure I can totally agree on this one. As an observer of billiards I have seen examples of all of the above situations. In your example, a ball with reverse english is capable of translating enough spin to another ball to make it spin at the precise speed that would prevent slipping on the frictionless surface would it not?
Ian, it is also possible to have two balls meet, with or without spin and have one or both, recoil along the same axis at which they met. The five balls hanging on strings desk toy is an example. Yes you can argue that the strings keep them in alignment during recoil but I think it is a little simpler than that. If it was such a precise balance that is reguired for that toy to work, you wouldn't be able to mass produce them and still make money.
Thoughts?