Had it been the parties' intent to limit the license to the Windows 1.0 interface, they would have known how to say so. Instead, the "derivative works" covered by the license are identified as the "visual displays" in the Windows 1.0 interface, not the interface itself. And there is nothing in the 1985 Agreement that indicates that it was intended as a product license restricting Microsoft and its licensees to the use of the Windows 1.0 interface as a whole.