d-pad patent
This URL points to the D-pad patent proposed on August 18th 1987: “a four-directional switch which can be turned on and off in four directions, which comprises a base plate having a plurality of electrodes formed thereon, a key top having an indication showing predetermined four pressing directions in an identifiable manner, a support member constituting a fulcrum between the base plate and the key top, a plurality of conductive rubbers disposed opposing to the plurality of electrodes so as to be in electrical contact with corresponding ones of the electrodes, and a sustaining member having the plurality of conductive rubbers fixed thereto and having elastic force for sustaining the conductive rubbers so as not to be in contact with the electrodes when the key top is not pressed.” The patent was proposed by Ichiro Shirai who is not the real inventor. It was Gunpei Yokoi who created this device but he was so into creating new devices that he asked Shirai to write the patent!
The following drawings extracted from the patent depicts the “prior art” (Game & Watch prior to the invention of the d-pad), the invention and the d-pad itself. Note that Nintendo planned to put the direction pad on the right! 
