Douglas Engelbart, one of those many Oregonians who did their best work in California, invented the mouse in 1963 as a part of NLS (video, demo app).

The first mouse worked by having two turning discs mounted perpendicularly. It works very differently than the ball or the laser mice we’re used to today. But suppose the first mouse did use a ball…

Now onto trackballs. Little known fact, but the first trackball was invented around 1950 by University of Toronto grads for a sonar application. (An aside: researchers at UofT can also say they invented multitouch in the early 80s—long before Microsoft or Apple or Jeff Han. So it really bothers me when articles such as this one in Wired do not mention Toronto’s contribution at all.)

Look at the photo of the first trackball. Really, all Engelbart would have hypothetically had to do to invent the mouse would have been to turn a trackball upside down.

So that’s the first design transformation: turn it upside down. What are other designs that can be created from previous designs by turning them upside down?