Aesthetics in user interfaces addresses font definitions, typesetting conventions, color combinations, graphics design considerations, high resolution for viewscreens, and the shapes of windows. Computer viewscreens are evolving into pictorial media, communicating information with visual immediacy. The more interesting interfaces make use of multiple windows, menus, icons, and other visual effects to waken and sustain user interest and effectiveness. A pretty window is a viewscreen window with the dimensions of a golden rectangle, a rectangle whose width and height form the golden ratio of Euclid. Psychologists believe golden rectangles are aesthetically more pleasing than arbitrary rectangles, and subjects tend to select them in preference to other rectangles in tests.