 The doctrine of 'Sound, light and rays' is intimately connected with the Dzogchen teaching of the 'three aspects of the manifestation of energy'.Though thoroughly interpenetrating and nonlocalised, 'sound' may be understood to reside at the heart, the 'mind'-wheel; 'light' at the throat, the 'voice'-wheel; and 'rays' at the head, the 'body'-wheel.Some Dzogchen lineages for various purposes, locate 'rays' at the Ah-wheel (for Five Pure Lights pranayama) and 'light' at the Aum-wheel (for rainbow body), and there are other enumerations.