Dasher

" Dasher is an information-efficient text-entry interface, driven by natural continuous pointing gestures. Dasher is a competitive text-entry system wherever a full-size keyboard cannot be used - for example; when operating a computer one-handed, by joystick, touchscreen, trackball, or mouse; when operating a computer with zero hands (i.e., by head-mouse or by eyetracker); on a palmtop computer; on a wearable computer."

http://www.inference.phy.cam.ac.uk/dasher/

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http://www.inference.phy.cam.ac.uk/dasher/TryJavaDasherNow.html