a. The derivation begins with the “chord of nature,” numbered as level 0. A voice-leading transformation in the upper voice leads to level 1, the
Ursatz.
After adding a secondary upper voice, a voice-leading transformation leads to level 2
b. At level 2 in the derivation there is a new arpeggiation in the upper voice (G–
E♭–C) before a new inner voice is added in counterpoint
and combined with the upper voice through unfolding to create a new upper voice at level 3
c. In the upper voice, the initial tonic third D–
B♭ is inverted by a transfer of D, making way for an expansion of the D–
B♭ tonal space.
A new inner voice emerges at this level in counterpoint with the bass
d. At level 4 the bass combines via unfolding with an inner voice
e. The addition of diminutions brings level 4 to the musical surface, making this the foreground level. This example shows just the most significant of these diminutions.
(Note: this is the same level as 15(d) because they are related by diminution, not transformation)