Pattern-crazy design duo Nicole and Petra Kapitza have released their first app for Apple's iPad and iPhone app, geometric™, which unsurprisingly makes patterns.

The sisters say that geometric™ is a powerful pattern designer and cool wallpaper creator rolled into one. All you do is swipe your finger across the screen and a new pattern is generated.

Patterns can can be saved to iPhoto, used as wallpaper or emailed to friends.

geometric™ costs £1.99 and, despite the naming of it, wasn't developed by ustwo™, but by Michael Kowalski of Contentment.

Kapitza recently released a book of patterns designs called Organic.