4. This fascinating zone is where the roof is married to the body. In the foreground you can see a body assembly moments before a robot positions a sunroof-equipped roof (seen poised for installation on the right side of the photo) into position and tack-welds it in place. If you look close you can see black beads of sealer that have been robotically added to the body assembly and roof bows. This sealer is one of the reasons the roof doesn't "flutter" when a door is slammed or a window is opened at speed.