pinball machine symbolizing the prostitute.
I recently made a certain realization about what's being expressed through the pinball machine scenes... I'm sure it's been discussed before but I figured I'd mention what was popping into my head at the moment.
The fee is paid, and the game begins. Look at the way one stands when playing pinball: With the pelvis against the front, hands on either side, against a long machine... oriented much like a woman on all fours (for lack of classier expression). It has a physical resemblance to sex. The machine even makes confirming noises, depending how well one plays.
In the first scene, Nana starts a game but doesn't pay any attention to it (as it was not a sexual position for her). She continues her conversation, while on the other hand, Paul walks up and focuses on the machine, getting slightly jerky and frustrated, losing the game and symbolizing the couple's sexual dissatisfaction with one another.
When Raoul is seen playing the machine, it's clear that he's no stranger to the game... He plays for quite a long time. As a symbol of his status as a pimp, he even manages to watch the girls as he plays.
So with that realization, I've come to enjoy playing pinball considerably more. Ha... bad joke.