In a film about magic and illusion, isn't it a shame that the makers cheat the audience who have waited patiently for the clever reveal. It's not so much a case of "how did they do that, it's impossible" as "that IS impossible". There's no magic trick at all, the whole conceit relies on a sci-fi teleporter/cloning machine which does not and never has existed. Well acted, well staged and filmed but the whole idea of the magic trick ending with a "prestige" is lost because, in this film, the trick has no prestige, just a sparkly device which, you feel, has been invented by the film-makers because they couldn't think up a clever ending. Twists and tricks are great in movies, provided they are believable and inventive. Doing the impossible is merely treating the audience as idiots.