The sound of air is wavering, its form zigzag, and its color blue. Its voice is heard in storms, when the wind blows, and in the whisper of the morning breeze. Its effect is breaking, sweeping and piercing. The sound of air finds expression in all wind instruments made of wood, brass and bamboo. It has a tendency to kindle the fire of the heart, as Rumi writes in his Mathnavi about the flute. Krishna is always portrayed in Indian art with a flute. The air sound overpowers all other sounds, for it is living, and in every aspect its influence produces ecstasy.