[nirmal]

Like the concept, reminds me of QuickWrite. However, I am skeptical of claims that text could be entered without viewing. At a minimum it seems that viewing would be required to target the center circle. Maybe this could be solved by "re-centering" the entire input space based on initial touch.

[dpatru]

The input surface could be marked so that the finger feels what is the home center and where the quadrant boundaries are. The marking could be done with ridges or indentations on the surface, or by vibrations or even sound.

[bilban]

There must be a way to create an indent, or some kind of tactile homing device.

[nirmal]

Sure thing. That is another way to hone in on the center. Some sort of tactile gravity well implementation. I think that if 5-ways on candy bar phones were actually joysticks instead of 5 buttons this may work better. And it could definitely work on devices with mini-trackballs.