The opening credit sequence is a modified version of a zen garden. This style of garden is often referred to as karesansui, which means "not using water."The two main elements of a Zen or karesansui (pronounced "kah-ray-sahn-soo-ee") garden are rocks to represent mountains (or islands) and sand to represent water. The sand used in Zen gardens is not beach sand; it is actually crushed or decomposed granite, small pebbles, or fine gravel. The particles of crushed granite are angular rather than round, so they can be more easily raked into patterns. Moreover, ripples in the sand or gravel represent flowing water or ripples in the ocean.