A group of designers has created a contender for the world's best jungle gym - a giant inflatable bubble which has endless lengths of rope inside. The unusual project, called String Prototype, has lengths of rope and cables threaded inside the bubble that can take the weight of a person, so users can climb around and explore. The cube’s designers are a Croatian and Austrian collective, Numen, founded by Sven Jonke, Christoph Katzler and Nikola Radeljkovic, who specialize in large-scale interactive projects. When the inflatable cube deflates the ropes get loose and lay on the ground, which means it can be easily packed away. [Photo/icpress.cn]