In short, a use case describes the interaction between an individual and the rest of the world. Each use case describes an event that may occur for a short period of time in real life, but may consist of intricate details and interactions between the actor and the world. It is represented as a series of simple steps for the character to achieve his or her goal, in the form of a cause and effect scheme. Use cases are normally written in the form of a chart with two columns: first column labelled actor, second column labelled world, and the actions performed by each side written in order in the respective columns. The following is an example of a use case for performing a song on a guitar in front of an audience.