On Being Square

This is a panoramic view of the carpenters finishing the first floor sub-flooring.  They had all of the right tools and a division of labor that was as efficient as it was impressive.  They really were a team.  This deck is approximately 50' x 30'.  They started from where this picture was taken and were finishing where you see them.  At the end of the process, all of the edges of the 4' x 8' sheets of flooring were striking the exact middle of the 2" portion of the 2" x 12" floor joists, the same as when the process started and everything was square and level.  Amazing!