Toys, Games and Hobby Products Design Boulderball Training Tool and Game by Martin Oberhauser The smallest bouldering wall in the world. Boulderball is the first combined training tool and game specifically made for climbers, finger-strength training and climbing technique. Inspired by climbers, the Boulderball packs an ideal climb-training tool and fidgeting game for climbers into a small ball that can be brought along everywhere. Through an innovative assembling system (plug and play) the climbing holds keep the structure together and provide the connection points for the primary structure.