Start three dominants up the wheel and let the lane carry you: 3⁷, 6⁷, 2⁷ — everyone can hear the 5⁷ coming. Don't play it. The tritone substitute takes its place and the bass, which was leaping in fourths, suddenly slides the last half step home. The chain works because the backcycle builds maximal certainty and the sub spends it in one move.