Design collective Numen/For Use was incepted in 1998 as a way for its members — industrial designers Sven Jonke, Christoph Katzler and Nikola Radeljković — to push the boundaries of architecture, design and conceptual art. They've collaborated on everything from furniture design to elaborate installations that invite the viewers to break the norms of how they ordinarily interact with space. Rarely do we see adults take off their shoes to bounce and play, but Numen invites their audiences to do just that. Their latest piece, String in Vienna is an inflatable, bounce house-like structure with an elaborate grid of cords that allow viewers (more aptly, participants) to defy gravity. Their other recent works include a levitating cave made out of clear tape in Tokyo and another inflatable structure with hammock-like netting hung strategically for optimal bouncing in Yokohama, Japan.