Literally, in German, gestalt means “form,” and refers in the abstract to the human desire to complete things that are aesthetically incomplete, or, in the parlance of gestalt psychology, to close open gestalts. As a basic example, in the Kanisza triangle illusion (Figure 3.1-1), the viewer perceives the presence of a bright white triangle where one is only outlined. When the brain sees elements that suggest a shape, it hallucinates the presence of a complete shape. Gestalt psychology explains this as a result of the brain’s desire to complete an uncompleted form, to close an open gestalt.