By the way, please tell Mr. Jagger I am not Maurits to him, but Very sincerely, M. C. Escher. According to the forum post that brought this all to light: "In an ensuing letter, Mick Jagger asked ...
M.C. Escher seems as puzzling as his art. He had friends, but only an early teacher was, apparently, a fellow artist. He didn't have an art dealer. He expressed little or no interest in the art ...