Although not officially confirmed, Ralf Hütter suggested that a second boxed set of their first three experimental albums—"Kraftwerk", "Kraftwerk 2" and "Ralf and Florian"—could be on its way, possibly seeing commercial release after their next studio album: "We've just never really taken a look at those albums. They've always been available, but as really bad bootlegs. Now we have more artwork. Emil has researched extra contemporary drawings, graphics, and photographs to go with each album, collections of paintings that we worked with, and drawings that Florian and I did. We took a lot of Polaroids in those days." Kraftwerk also released an iOS app called Kraftwerk Kling Klang Machine. The Lenbach House in Munich exhibited some Kraftwerk 3-D pieces in Autumn 2011. Kraftwerk performed three concerts to open the exhibit.