Six bolts fasten the tree house to two redwood trees and it's also cantilevered. Inside, the 10-by-12-foot room and a loft feature his signature reclaimed wood, geometric ceilings and stained glass portals as well as three large windows looking over the rooftops. The cream canvas cushions on the sofas have been hand-dyed by his friend Matt Katsaros using bark from the trees and the throw pillows and blanket are tie-dyed indigo - the best of Bay Area crafty cool.

This is Nelson's fifth tree house, but he started making pretty elaborate hideouts when he was just 10 years old, a young surfer living in Redondo Beach (Los Angeles County). No wonder; his father was a USC physics professor and inventor. He learned the history of surf shacks, shaping hisown with driftwood, concrete and palm fronds and he built patios into beach cliffs.

Tree house in Hawaii

After he was diagnosed with cancer at age 14, he was homeschooled by his mother and spent hours drawing, painting and doing ceramics. After completing a bachelor's in fine arts at California College of the Arts he left for Hawaii to build his first tree house, using hand tools and material found on the beaches and forests. When he came back to San Francisco to do a show of his paintings at Needles & Pens store, he made another tree house using recycled urban stuff and lived there for a month.

Pushing his minimalist ideals and working with what was on hand, he built a camper shell over his Honda Civic and lived