Here you an interesting concept that once turn real becomes almost a complete, behold the Grip UI from Docomo. The theory, and reality, is that it is rather difficult to use your smartphone in a confined environment like a train for example. It is indeed at pick-hours almost impossible to use both hands with your smartphone without a) Disturbing your neighbors and b) Standing still without disturbing anyone when the train is moving. Strong from this two very basic points the R&D section of Docomo devised a very interesting plan by adding pressure senors on each side of the phone as well as developing a dedicated UI than can be control by just pressing your phone in certain areas.
As the video above will demonstrate the system works, at least when someone from Docomo gives you a demo, however once you have the phone in your hands this is actually a complete different story! Sure with time and patience you can make it work but you needs to have giants hands with alongside the dexterity of a robot. Even worse certain “gesture” will at best give you cramps and at worse you may accidentally drop your phone as soon as the train conductor hit the brakes. So yes, interesting concept but poorly designed.