It's almost three years since anyone did this puzzle It's a pretty one. Spent some time with a guy who played when I was young and foolish. Ditched the guy; liked playing pool tho. Wish we had a table at home.
There are many different pool games. In the game of 'eight-ball', one player shoots for the balls numbered 1-7 and the other for the 9-15 balls. Whoever sinks his all his target balls first gets to shoot at the 8-ball, and it's illegal to shoot at it or use it in a combination shot otherwise. So when a player is "behind the 8-ball" he is unable to shoot and loses his turn.
One of these days, with my spring cleaning caught up, I'll challenge a fellow resident to some pool just for the fun of it.