Everybody's Guide to the Magical World of QR CodesImagine you could hold your mobile phone up to an image, and magically summon any information you wished.You see a movie poster and wonder if the movie is worth seeing. Zap! You're watching the movie's trailer. You see a restaurant menu and wonder about the food. Zap! You're reading reviews from people who ate there. You're at a subway stop. Zap! You're seeing the actual arrival time of the next train. You see a magazine ad for a product and want to buy it. Zap! You've placed the order.How does this magic happen? With something called a QR...