Metaphor

thumb|upright=1.35|1835 etching by George Cruikshank illustrating the metaphor of describing strong weather as "raining cats, dogs and pitchforks" A metaphor is a figure of speech that, for literary effect, refers to one thing by mentioning another. Thus, it invites the audience to make a comparison between two normally unrelated entities or ideas, which may provide clarity or identify hidden similarities between them. Metaphors are usually meant to create a likeness or an analogy.

fraudulent medication

representation of a system, made of the composition of concepts

use of a single metaphor or analogy at length