Free Spirit Spheres

Free Spirit Spheres are "durable spheres [which] can be hung from the trees ...making a treehouse. They could also be hung from any other solid objects or placed in cradles on the ground. There are four attachment points on the top of each sphere and another four anchor points on the bottom. Each of the attachment points is strong enough to carry the weight of the entire sphere and contents."

They contain shelves, cabinets, a bed, and windows. If I had a tree, I would want one.