In this module we describe some of the mathematics behind billiards. We will first look at the
shape of the table: rectangle, square, circle, ellipse, etc. In general the table can have any
form, from very simple to very complicated. We will also explain some
puzzles related to billiards, some of them having unusual solutions. Even if the
rules of billiards are simple, the solution of these puzzles can become complex,
depending on the situation.