We envision a whole lot of Candid Camera shots with this one. A group of scientists has made a billboard that talks. That’s a bit of exaggeration but not much. The billboard is made of a digital paper that responds to touch by emitting sounds. It’s not wholly interactive in that the sounds that come out have to be prerecorded, but the idea is still there. Conductive inks are the key, and speakers installed in the billboard are the mechanism. The prototype is in the form of a travel brochure, which enables viewers to touch a certain part of the display and instantly hear a description of the corresponding destination. The scientists say that such technology could be used in the future to describe foods and other goods. We also wonder whether it could be used in place of braille, so that blind readers could have their books read to them. Now that’s the sound of progress.