The concept of unity describes the relationship between the individual parts and the whole of a composition. It investigates the aspects of a given design that are necessary to tie the different composition/ parts together, to give it a sense of wholeness or to break it apart and give it a sense of variety. When all parts of the house are in perfect scale, it provides an appearance of unity. In home furnishings, each article must be in scale with the room and also with other furnishings and articles in the room. Ultimately it means that the structural parts of each article must be in scale with one another and to the whole, by which unity is achieved. Unity in design is a concept that stems from some of the Gestalt theories of visual perception and psychology, specifically those dealing with how the human brain organizes visual information into categories, or groups.