The Three Walls of the Temple represent the Three Bodies of Man- gross physical, subtle physical and causal, Sthoola Sarera, Sookshma Sareera & Karana Sareera. The Self ( Deity of Temple ) is encased by these bodies, sarvam avritya thishtathi. Some temples have mirrors. You can see your Image and you will be able to say like Goethe’s Faust ” Am I a God then? . Yes, I am. In these pure features I behold, Creative Nature to soul unfold “.