Is there a tested method or recognised structure to be used for pacing the increasing level of horror as events unfold? I recently watched Below, which is a good example as any of gradually building tension and scares throughout a story as it moves toward the final act. The director summed up his plan in a behind the scenes feature; Act 1 - Moody, Act 2 - Creepy, Act 3 - Terrifying. Being a horror fan I've seen a lot of films that follow this basic structure, gradually getting more unsettling as the creepiness factor of events increases and possible rational explanations dwindle. I've noticed at just before the final act there is usually some event that drastically reduces the number of characters remaining. There's enough other plot similarities that surely someone has written a good article or two about it. Are there any studies into the structure of films like this, or good resources to help when trying to plan out the pacing of horror tales? I'm hoping to write one of my own. (: