Changes
http://img.over-blog.com/481x475/1/27/40/16/Evolution-joystick/Joystick-evolution-Speedking-analogue.jpg
this one is the Analogic one.
http://www.gamersgraveyard.com/repository/nes/peripherals/images/Konix_Speedking.jpg
Nintendo NES model.
Also 3-4 buttons may have existed (for Sega Megadrive).
