4. Tactus Technology is the developer of a new tactile user interface for touch-screen devices. Tactus provides a new dimension of user interface with a fundamentally unique solution: application-controlled, completely transparent physical buttons that rise up from the touch-screen surface on demand. With the buttons enabled, users can push and type or rest their fingers as they would with any physical button or keyboard. When the buttons are disabled, they recede into the screen, becoming invisible and leaving a smooth, seamless flat touch-screen with maximum viewing area.