There is a scene in Inception (2010) where Ariadne builds an infinite mirror, alluding to the thematic of possible worlds in the film. This scene visually mimics the moment in Citizen Kane (1941), where Kane sees himself reflected infinitely:
And here's a photo of Gilles Deleuze projecting himself infinitely for good measure.
Whereas in Citizen Kane, the reflection of images might allude to the many 'Kanes' created in the public eye, Inception's 'dreams worlds' are more visceral in that the characters actually inhabit them, even if only temporarily. This scene in Inception is different from other uses of this visual trope, however, as Ariadne presses against the infinite mirror, which breaks it to reveal a single, long road. While allowing the possibility of many worlds, Ariadne affirms just one of the many.
Throughout the film, her character serves a probing function. She discovers the secrets of Cobb's dream world, and explains Inception's dream-physics to the audience. Her declarative statement in breaking the glass and revealing a singular possibility is significant in terms of the end of the film, where Cobb's top comes spinning to a halt (or does it?). In spinning to a halt, the top affirms that Cobb's present experience is reality and not a dream.
Deleuze's pose between the mirrors illustrates his interest in the time/crystal-image, but ultimately his cinematic ethics was based on the affirmation of a singular existence -- or a 'belief in the world'. Here, 'the world' is something akin to what Deleuze described as life -- not fantasy, not an ideologically-inflected existence, but pure lived experience. As David Rodowick and Ronald Bogue point out, this ethics is based not only on film's ability to inspire a 'belief in the world' but also 'one's ability to change the world'. Because Inception is all about the layering and getting lost in dreams, the world becomes a questionable state. Cobb finally changes his world by taking action to become reunited with his kids in reality. In the very end, however, the film asks: is this reality, or is Cobb just playing in a fantasy world?
Of course, I think the film is ambiguous about this point -- it is questionable as to whether the top stops spinning or not -- I also tend to think the way it wavers at the end suggests that Cobb is in fact back in 'the world'. Does this mean Inception poses an ethical statement by illustrating how Cobb has indeed returned to 'the world' in his desire to change his reality, rather than hiding in the dream world he has created for himself? Although it would be difficult to say it inspires an ethics to the filmgoer the way a truly ethical film would, this sort of ethical question does seem to be at the heart of Cobb's predicament throughout the film.