It's subtle, but Popular Science sells its cover

It's called "augmented reality". The July issue of Popular Science has a cover sponsored by General Electric which is so subtle that the only way the G.E.-branded affilliation is known to the reader is if they hold the cover up to a webcam.According to a story in the New York Times, showing it the cover signals the computer to display a sponsored site with Flash-based 3-D images of the windmills