Apple's invisible buttons

"Apple is (at least) thinking about how to bring elements of touch computing to all devices by replacing buttons and other controls with capacitive controls which appear only when needed.  ...  The patent describes a way to create backlit micro-perforated holes on the aluminum casing of a MacBook or other device which could be used for buttons on the lid when the laptop is closed or below the keyboard when it is open.  ...  The input appears invisible to the user because it would be made of the same material as the housing it is contained in. The use of “invisible” backlit holes could make the input selectively visible or invisible for the user."   http://techcrunch.com/2010/04/29/apple-patents-invisible-button/