Whatever the case, Willys provided a prototype called the Quad (for the 4x4 system it used) and Ford the Model GP prototype -- which didn't actually stand for "General Purpose," as many might believe.

The result was the Willys Quad, which evolved into the Willys MB after further refinements. The vehicle, later known as the “Jeep,” became indispensable during WWII, with Willys producing ...