The mirror is in every room in the ballet world, because ballet dancers are constantly looking at themselves, studying themselves, and maybe even judging themselves. All the time. So it was very clear to me that the mirror was a major character in this film. And the film is also about doubles. Your reflection is your double, isn’t it? So it just became a really important part of the film. And very early on we started to think of all the different types of tricks we could do with mirrors. - Darren Aronofsky