Metaphors are used in poetry as well as in everyday language. Metaphors map concrete concepts to abstract concepts. They may be formulated in the following sentence form: X is Y. "Life is a stage" is an example of this from English. Here, the concrete concept of stage is mapped to the abstract concept of life. This mapping also applies to parts of these concepts: people correspond to actors, life corresponds to stage and people's actions correspond to actors' actions. In this mapping, the more concrete domain is the "source" and the more abstract domain is the "target".