Out of the billiard game variants, what's this called?

Question:There are many variants of Billiards, pool, snooker and the like, but I've seen it played where they place champagne glasses on the table (and I think you have to avoid hitting the champagne glasses)
First of all, what's the name of that type of game with the champagne glasses on it.
Secondly, the purpose of the glasses. (To make it more difficult, I assume.)
Thirdly, can the glasses be arranged in any way you like? Or are there set patterns?

Answers:

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