It's easy to use and to remember. Chanting OM unifies your perceptions so you can sense yourself as an integral part of the universe. OM is a great mantra for anyone. While a mantra is meant to soothe the body and mind through sound, a mandala is meant to center the mind through sight. Mandalas are beautiful, usually circular, geometric designs that draw your eye to the center.
Mandalas represent a pilgrimage to enlightenment.
Mandalas are a metaphor for the spiritual path of the mind and body. This well-known mandala appears in the floor of Chartres Cathedral in France. Spiritual pilgrims literally walked through the mandala to attain spiritual insight. Get a pencil and try walking the Chartres mandala by tracing the path you would take to reach the center and then return from the center to the world again. Using mandalas and mantras together is a wonderful way to meditate because the combination of aural and visual stimulation awakens and clarifies your mind, body, and spirit in multiple ways.