Creative Applications▸ Modulares Interface B.A. – Physical controller interface for iPad:

"Created by Florian Born, Modulares Interface B.A. is a physical interface for iPad comprised of knobs, buttons and sliders to provide precision and haptic feedback when operating a digital interface.

"These controllers expand the usage of a touch device with a haptic feedback while adjusting parameters. By using magnets, the different controllers can easily be arranged onto the iPad."

What a great idea. Make sure to watch the video to see how it all fits together.