Demotic Script or Da Mata ik (like Deva Nagri) from famous Rosetta Stone. I have often found evidence of scripts being turned upside down, read in wrong directions and so on. There is a script called Omyad Script from Babylonia, and when you turn it upside down, it has Devanagri Characters.
Flipped Horizontally and Vertically (below)
Flipped Horizontally (below)
Flipped Vertically (below)
Original (below)