They reflect the personality and ambience of a room and are considered to be softer and therefore more feminine. In any one room, the various forms should be harmonious and composed of similar types of lines. One of the most important tenets of interior decoration is that comfort and function should not be sacrificed in order to use a certain form. For example, if a chair is pleasing to look at but uncomfortable to sit in, it is not functional, and is not good interior design. Generally speaking, rectangular shapes are more pleasing to the eye than square shapes.
Rectangles are frequently the dominant shape in a room.
A square shape generally suggests a rational, stable form with no directionality. A circle implies unity and completeness. A triangle is a stable, but dynamic shape. The surface of an object, its smoothness or roughness, is another important decorating tool. The use of several complementary textures can add variety and keep interest alive.