A user interface device, comprising: a display device; a keyboard (103, 113); a mechanical metamaterial region (105, 115) located over the keyboard (103, 113); at least two actuators (107, 109, 117, 119) partially or completely embedded in respective opposite ends of the mechanical metamaterial region (105, 115) and configured to stretch or compress the mechanical metamaterial region (105, 115) by pulling or pushing on the mechanical metamaterial region (105, 115) in respective opposite directions when the at least two actuators (107, 109, 117, 119) are activated, wherein the mechanical metamaterial region (105, 115) has an internal structure that is alterable by the stretching or compression of the mechanical metamaterial region (105, 115) caused by the at least two actuators (107, 109, 117, 119), and wherein at least one of a shear modulus or a bulk modulus of the mechanical metamaterial region (105, 115) changes in response to the alteration of the internal structure by the stretching or compression caused by the at least two actuators (107, 109, 117, 119); and a control unit in communication with the at least two actuators (107, 109, 117, 119), and configured to determine whether an application running on the user interface device is a video viewing application, to determine that the keyboard (103, 113) is to be hidden from tactile perception in response to a determination that the application running on the user interface device is the video viewing application, and to activate the at least two actuators (107, 109, 117, 119) to alter the internal structure of the mechanical metamaterial region (105, 115) in response to the determination that the keyboard (103, 113) is to be hidden from tactile perception. a display device; a keyboard (103, 113); a mechanical metamaterial region (105, 115) located over the keyboard (103, 113); at least two actuators (107, 109, 117, 119) partially or completely embedded in respective opposite ends of the mechanical metamaterial region (105, 115) and configured to stretch or compress the mechanical metamaterial region (105, 115) by pulling or pushing on the mechanical metamaterial region (105, 115) in respective opposite directions when the at least two actuators (107, 109, 117, 119) are activated, wherein the mechanical metamaterial region (105, 115) has an internal structure that is alterable by the stretching or compression of the mechanical metamaterial region (105, 115) caused by the at least two actuators (107, 109, 117, 119), and wherein at least one of a shear modulus or a bulk modulus of the mechanical metamaterial region (105, 115) changes in response to the alteration of the internal structure by the stretching or compression caused by the at least two actuators (107, 109, 117, 119); and a control unit in communication with the at least two actuators (107, 109, 117, 119), and configured to determine whether an application running on the user interface device is a video viewing application, to determine that the keyboard (103, 113) is to be hidden from tactile perception in response to a determination that the application running on the user interface device is the video viewing application, and to activate the at least two actuators (107, 109, 117, 119) to alter the internal structure of the mechanical metamaterial region (105, 115) in response to the determination that the keyboard (103, 113) is to be hidden from tactile perception.