After Lucid Touch prototype A new, smaller prototype created by Baudisch and his student Gerry Chu at the University of Toronto takes the idea further. Called NanoTouch, it has a 6-centimetre (2.4 inch) screen and a touch pad of the same size on the back . It can detect the touch or press of a finger, allowing the user to move a tiny cursor around and click and drag with it.Read More
On this device the targets can have half of the size of targets on iPhone.
The same concept was introduced for a table at UIST 2006: