Voice Response Paper

--Imagine paper/ink combo that responds to simple commands, i.e. 'hilight scores' or 'bold total'. The technology is almost up to it: someone's invented ink that can 'print' solar cells; how far big a leap is it to imagine an ink that can brighten or darken on command? Someone else has paper with an embedded grid that transmits from a special 'pen' via bluetooth to a computer; so how far are we from reversing that connection? Somewhere we're real close to a melding of paper that has 'power' to an ink that can emphasize or hide text. --I'm thinking it's about the only thing that will keep newspapers from going belly up too...