Going to the cinema these days can inspire a special sort of deja vu. We're not talking about the constant churn of sequels or remakes, or attending a special screening of either Groundhog Day or that one scene of the cat from The Matrix (we're not sure why any cinema would partake in the latter), by the way; we're talking about the fact that every film seems to be exactly the same. You can take films as diverse as, say, Guardians Of The Galaxy, The Great Gatsby and Gravity, and still come away feeling like that was something familiar about each of them. They had something in common, besides taking place in space. Unless you're a screenwriting geek, then you probably haven't been able to put your finger on what exactly those similarities are. What exactly do adventures of Peter Quill, Nick Carraway and Dr Ryan have in common? Well, they are all slavishly devoted to a set of cast iron rules that every screenplay follows. You know how people complain about big budget Hollywood films being formulaic? That's because they have a literal formula they follow in order to write a successful movie. You can see why they do it those big budgets are huge investments, and huge gambles. You want a return on that investment. Why wouldn't you stick to a tried-and-tested method to make all your films by? The screenwriting seminar industry has dominated Hollywood for decades, playing on the anxieties of executives, directors and writers alike. Movie veteran John Howard Lawson wrote tons of books on the subject (before he got blacklisted), Robert McKee picked the ball up with his Story: Substance, Structure, Style and the Principles of Screenwriting lectures, and recently tinsel town has fallen under the thrall of a book called Save The Cat! In those lectures, book and self-help guides, you can find the ten rules that make every movie exactly the same.