The "Spherical Tree House" concept borrows heavily from sailboat construction and rigging practice. It's a marriage of tree house and sailboat technology. Wooden spheres are built much like a cedar strip canoe or kayak. Suspension points are similar to the chain plate attachments on a sailboat. Stairways hang from a tree much like a sailboat shroud hangs from the mast. Spherical architecture has many unconventional features. Conventional buildings separate walls, ceiling and floor with hard lines. In a sphere the walls and ceiling merge into one. The function changes but the form remains the same. It is a unified structure with one continuous wall. I call this uniwall construction. There are only 2 sides to a sphere, inside and outside.
from: Tom Chudleigh