A joystick adapter is provided for mounting over the depressible buttons of a directional keypad on a video game controller. The adapter includes a joystick having a knob and a separable base. The knob is configured for manual manipulation, while the underside of the base is configured to contact and...http://www.google.com/patents/US5883690?utm_source=gb-gplus-sharePatent US5883690 - Joystick adapter for a directional keypad on a game controller
