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Secret code in Ex Machina(r/movies)
If you’re interested in supllementary reading after seeing Ex Machina I recommend Superintelligence: Paths, Dangers, Strategies by Nick Bostrom. He goes into some depth as to the dangers related to trying to contain a strong AI and even the possibility that a sufficiently well informed AI could employ social persuasion to achieve their goals. All relevant to Alex Garland’s movie.
It’s hard to say too much about it here without being spoilerish but I have to think that Garland read Bostrom’s book during his research. There’s a lot of overlap.