If all of Le Pont du Nord's games, rules, and neuroses point back to a single theme, it is the fear of death, and the possibility (or impossibility) of cheating death. It's difficult to say more than that, because for everything you could say about Rivette's attitude towards mortality, the opposite would likely be just as true. Death is the chief subject of comedy, and at the same time the tragedy for which all comedy exists to compensate...