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 on a palmtop or wearable computer, or when operating any computer one-handed (by joystick, touchscreen or mouse) or zero-handed (eg, by head-mouse or eye-tracker).
Choose Applications ▸ Accessories ▸ Terminal.
Enter: sudo apt-get install dasher
Enter: dasher
Dasher may also be installed from the Applications ▸ Add/Remove dialog. In either case, it may later be launched in these ways: