Start the backcycle one station earlier and the machine runs itself: 6⁷ aims at 2, 2⁷ aims at 5, 5⁷ aims home — each dominant resolving into the next dominant, the guide-tone escalator falling three links in a row. This is Sweet Georgia Brown, the Salty Dog engine, and half of ragtime: one crank of the circle, every landing also a push.