Once upon a time, there was a grand ole wizard called Model, he was the source of all knowledge in the small town of Hobshire. He often kept for himself and didn't like the inconsistencies of the common folk, called the views, them being an unreliable source of information. Their information stayed unprotected and mutable where they lived, out on the streets or in their puny homes. Model only talked to the mayor of the humble town, Ms. Controller. As faithful as he was, Model answered all of Controller's requests, and controller decided what information should be handed out to the views, the common people, of the village. This way, Model and Controller had the sole right to information and the control of this information, together they ruled for a long, long time.
This tale is, of course, based on the common MVC design- a super popular architectural pattern for software, particular web applications. Although most languages do not come with MVC capabilities, there are popular frameworks that include this functionality out-of-the-box. MVC works by separating the different parts of an application, making it easier to reuse and rebase code.
Comics retrieved from https://pragtob.wordpress.com/2013/02/23/710/