In the Iyengar Yoga System there are two half moon poses Archa Chandrasana meaning half moon pose and Parivrtta Ardha Chandrasana known as revolved half moon pose. The moon shows two sides of a half at its different phases. Practice Half Moon pose during the first quarter moon and revolved half moon poses during the fourth quarter moon. This is a way to let nature inspire your yoga practice. Moon poses are said to be cooling poses just like the moon is a cool orb.