The visual physical configuration and stealth shaping have been claimed to be influenced by foreign aircraft, including the F-22, F-35, F-117, Mig 1.44, Mig-31, Rafale, and Eurofighter Typhoon, according to an opinion piece published in The Diplomat by Rick Joe. Joe adds that the J-20's external physical configuration is a logical development of Chengdu's previous canard-delta designs: the Chengdu J-9 - particularly the "twin tail, side intake, canard delta" J-9V-II - from the 1960s and 1970s, and the Chengdu J-10 Furthermore, Joe said that stealth shaping is a much more universal and consistent trait that leaves limited room for variety, and that future international designs will likely reflect this.[100]