Formulas
In movies, video games, television commercials, songs, and novels, it might occur to you that there are some trending themes. It may seem as if two movies, games, commercials, etc. are similar in the plot, but different stories. When two types of stories are similar, they are most likely following the same formula.
For example, on Lifetime, a movie channel, there are days where all of the movies relate to each other. For example, a murder mystery day. During this string of shows there are many different stories that all follow similar plots. These plots would be considered a murder mystery formula. By the end of the movie marathon you can usually guess what is going to happen next, and how the movie is going to end. For example, everything starts out normal, weird things begin happening, people begin getting killed, but when it's time for the main character to get away there's a huge struggle that ends with the main character hardly escaping death. The killer usually gets away, or the main character may think they killed the killer, but the movie ends with the killers eyes opening. This would be an example of a murder mystery formula.
Formulas explain why some movies are so easy to predict, but when a movie follows a formula, it makes the story a typical plot. In each formula there is usually a love story, a hero, and a bad guy or tough situation.