Yantra - Harnessing the Power of Mystical Geometry. Yantra. By Swami Ayyappa Giri. Purohit-Acharya, Yogini Ashram, California USA. Article Published During Sacred Navaratri, 2016. Then Shiva Mahadev spoke to Parvati, "O Devi, Because it restrains suffering due to desires, anger and karma, it is called Yantra..