Dear Sir,
I read somewhere that Shri Vidyaranya was a Gayatri upasaka who performed many purascharanas of Gayatri and he received Her darshan only when he took up sanyasa at a late age. This story goes that angered by this, he cursed the Goddess to turn into stone (for having been a stone hearted mother) and she trurned into a yantra. Apparently this yantra is worshipped in Shringeri.
However, when I made enquiries in Shringeri about this, I was told that there is no such yantra. Can you or anyone throw light on this?
Also in shastra is there any record of Yantras for the Gayatri mantra?
There is also a story about the Hukka-Bukka and the rain of Gold that helped in establishing the Vijayanagara empire.
It is interesting that the other great tapasvin who was a bulwark in building an empire of dharma Shri Swami Samartha Ramadasa was also an upasaka of Gayatri.
Kind Regards,