The same technology could be used to create an invisible mouse. The camera would be focused on the spot on your desk where the mouse usually is. An accompanying program would cause the radio buttons, check boxes, etcc. on the screen to react when the fingers on your hand, converted into a miniature mouse pointer, tapped the desktop. If things were going really bad you could turn your hand palm up, extend its middle finger, and shoot a bird, deleting whatever was on the window that was currently active on the screen (maybe with an explosive sound effect). If you didn't want shooting a bird to equal delete, a program feature would let you change the hand signal to something else of your choosing, maybe having it do the same thing as clicking on the 'undo' button does.