Like the Alice in Wonderland iPad app, this retooling of a classic children’s tale Three Little Pigs is noteworthy for its design. The Three Little Pigs and the Secrets of a Pop-Up Book not only translates to the iPad the interactivity of a traditional pop-up with finger-activated swinging line-drawn illustration cut-outs, the app also adds a digital twist: there’s an ‘x-ray’ view of the picture that reveals the sliding mechanisms and spinning gears. Check out the video above for a demo.