Oh he's hardly a hobbyist. :) From his biography: https://langorigami.com/about-robert-j-lang/ https://langorigami.com/about-robert-j-lang/ Robert J. Lang has

Oh he's hardly a hobbyist. :) From his biography: https://langorigami.com/about-robert-j-lang/ https://langorigami.com/about-robert-j-lang/ Robert J. Lang has been an avid student of origami for over fifty years and is now recognized as one of the world’s leading masters of the art, with over 700 designs catalogued and diagrammed.