I’ve noted some recent commentary on “mouse gestures” in the Opera browser and the game Black & White (sorry, I’m too tired to dig up links and references). The idea of gestures came up back when I was doing pen user interface programming at GRiD. The use of pie menus was often discussed as being ideal for the pen interface. You’d tap the screen and/or click and a nice round menu comes up around the point you touched, and every selection is equidistant from where your pen is. Beautiful for Fitt’s Law. No dragging down two inches to get to your selection. Where do gestures come in? Well, the pie menus would be multilayered, so picture your top level “File, Edit, View, etc” menu being in a circle, and when you pick “File”, you’d get “New, Open, Close, etc” in the next circle. Once you learn where everything is, your menu picks get faster and faster and basically become equivalent to gestures. I remember doing a bit of implementation on a pie menu system … I did a lot of math to get those darn circles and pie slices to come up where I needed them to. But it was a good learning experience, even if it didn’t go anywhere. Nowadays, people are experimenting with Java ones and sometimes I see psuedo pies in computer games.