When correct progression increases the distance between the top and bottom notes of the upper parts, this does not matter:
| Good: | |
| [[Listen]] |
But it would be distinctly bad to fill in the second chord thus:
| Not good: | |
| [[Listen]] |
Hence it follows that the distribution of intermediate parts is a question of the greatest importance. Nothing is worse than writing chords, the upper and lower parts of which are separated by wide, empty intervals, especially in forte passages; in piano passages such distribution may be possible. Progression in contrary motion, the upper and lower parts diverging by degrees gives rise to the gradual addition of extra parts occupying the middle register:
| Schematic Example: | |
| [[Listen]] |
When the voices converge, the middle parts are eliminated one by one:
| Schematic Example: | |
| [[Listen]] |