All four voices in the same direction · Rules
Between two root-position triads, the four voices do not all move up or all move down. In the final cadence it is allowed if at least one voice moves by step.
- All four voices in the same direction: Between two root-position triads, the four voices do not all move up or all move down. In the final cadence it is allowed if at least one voice moves by step. (Piston, ch. 3, pp. 34–35)