X IS FOR X-RAY

More a showcase for the possibilities of iPad design than a primer on X-ray technology, this intriguing app is stuffed with lively activities and eye-catching visuals.

As in previous show-stopping iPad apps from TouchPress, March of the Dinosaurs (2011) and Solar System (2010), education and reference are excuses to display gorgeous images that can be rotated and played within a variety of ways. In this case, the 26 A-to-Z objects are items that were X-ray photographed by Turvey, who in his study of everyday objects in the 1990s showed the fascinating inner workings of motorcycles, a human hand, a teakettle and other objects. This app collects them, pairing each object with a page of text (typically a history, assorted facts or, in the case of "Nuts," a recipe for almond biscotti), a short set of couplets read by actor Kerry Shale and the X-ray view itself. This can be viewed by swiping downward on the object. A black top hat, for instance, reveals the ghostly image of a rabbit inside. The rhymes are lively (for "Engine": "In an engine gas explodes. / Pistons jump like tiny toads"), and the text write-ups are fascinating, if a little wordy.

While the haphazard nature of its subjects ("Drums," "Jack-in-the-box," "Whistle") make it less useful than a guide to the universe or a dinosaur encyclopedia, this is still an excellent plaything, built by artists who clearly know how to design with an eye for delight on the iPad.