An apparatus includes an optically transparent sheet having an electrically conductive layer, an electrode element, and electro-vibration circuitry configured to provide a time-varying voltage signal across the electrically conductive layer and the electrode element so as to cause a user to experience electro-vibration in a first body part of the user when the first body part is moved across an exterior surface of the optically transparent sheet while a second body part of the user is in contact with the electrode element.