The ability to play pool has always been one of the more renowned features of this game (right alongside the strippers). This effect is much easier to create than it seems, because the simple physics of the pool ball are automatic.
Create your pool table. Place
R key to floor-align them. Place
STRIPEBALLs (#901) and
QUEBALLs (#902) on the table. None of the sprites are autosized in-game, so resize them realistically. Alter their palette values for variety (you can't quite match the standard pool ball colours... purple is missing). Use a palette value of 12 for the actual cueball.