I'm being nostalgic, Facebook just tossed up this memory of an evening I spent with my old pal Lyle Tuttle, when I even got a photo of the little Borromean triangles / Valknut I once put on his forearm. I miss him.
An ancient Moorish symbol supposed to bring good luck and ward off the evil eye. Used in the TV show M*A*S*H* on the "swamp" door, (the surgeons' quarters), and on the book covers of the works of William Summerset Maugham.