Bubble Hold for rock climbing (Q54630)

Climbing hold for indoor rock climbing. Accepts a 3/8" bolt. The openscad puts random spheres (with random offset and number of facets) around a central cube to ensure a good attachment point. Play with the seed, add more spheres, go nuts! Tested on a bouldering wall, SportRock in Sterling VA. I think it'd be better to enlarge it, but of course I was worried about strength. The size that it is, you can't really crank on it so it's stable, if a bit slippery.