Optimus Tactus by Artemy Lebedev is a unique keyboard concept that has no physical keys. In fact this keyboard is a display and any its part can be programmed to perform any function or to display whatever you wish.
The Optinus Tactus keyboard is very comfortable to use. Apart from its basic function, it can be used as an additional display. The keyboard supports a great variety of characters, even rare ones such as such as Ancient Greek, Georian, Arabic and many others. The only disadvantage of the device is that the user is very likely to lack tactile sensations while typing, however, most likely, the user will get used to such unusual typing very soon.