This old photo is of the Op 200 tent interior. The ornamental wall on the left was an experiment Bill assembled with a prototype, using a patterned fabric for an interior second skin sewn to one of the regular white panels. "A kind of wallpaper effect," Bill said. "And when it's sunny and bright outside, it will function like a stained-glass window." I didn't like this particular fabric and preferred just the white, with shadowed patterns forming from tree branches and the curved seam lines. "But some people like wall paper," he insisted. And he was right; some did.