The physical environment of a psychiatric facility can, by careful design, provide both a safe and a supportive base for the treatment program. One requirement is an environment that is not monotonous; the lack of adequate stimuli leads to boredom, disorientation, and abnormal behavior. Visual stimuli are essential; they can come from changing patterns of light (preferably from the outdoors), variations in texture, colorful graphics, and variations in color value as well as in the colors themselves. Visual effects can also be used to improve the traditional long corridors, which foster alienation and disorientation, and to cause spaces to appear larger or smaller. Allowing patients some control over their environment, by encouraging them to bang personalized decorations, rearrange furniture, or participate in renovations, can relieve frustration and the sense of helplessness.