Jason Hayburn of Shelter Design Studio says that this treehouse was built for the grandchildren of a couple who live on a wooded lot. Located in a natural clearing, it's constructed out of cedar and has reclaimed windows and a standing-seam metal roof. "The owner wanted the treehouse to look like a quaint cottage in the woods," says Hayburn. "It has an L-shaped floor plan with a half-round deck that connects the two legs. The kids enjoy running up the stairs on one side and then down the stairs on the other."