Both computing pioneers were part of the team that developed a conceptual computer system called oNLine System (NLS). Many of the functionalities within NLS would eventually emerge on actual PCs over the next few decades including graphical user interfaces, online text editing, video calls and hypertext.
Not to forget, the computer mouse itself was built by Bill based on the concept and rough sketch by Douglas. As you can see from the image above, the first computer mouse looked quite different from the mouse that we know today. Eventually, the mouse together with NLS made it into the computing history book when they were presented in 1968 during a landmark demonstration that has since been nicknamed as “The Mother of All Demos”. Decades later, almost all of us still depend on the mouse to get things done on our computers. To that, we thank you, Bill. (Source: The New York Times // SRI International // Computer History Museum. Images: SRI International.)