It all started with the back yard swing set, Once upon a job, in an IT/computer room, I ran across three 6' x 6' steel IT frames and six  2' x 6' steel panels used to attach to the standing steel frames for computer shelves, I brought them home with no particular use in mind, it didn't take long for the creative energy to manifest. I used two of the steel frames and the panels to create a roof deck over the old swing set and the third 6' x 6' steel frame was placed high up in the tree; and there upon it, a tree house was built.