Prolonging the Fundamental Structure (cont.)
Prolongations of the Fundamental Structure (Mixture)
Mixture is an embellishment rather than a diminution - it is not derived from the rules of strict counterpoint. It describes the flattening or sharpening of scale degrees and it usually appears in the first level middleground in connection with as shown below.
Here it has the effect of changing the mode from major to minor and back again. Mixture of is often found in the middleground of the Minuet and Trio movement of a sonata or symphony.
If the example below were the first level middleground to such a movement the Minuet would be in the major followed by a Trio in the minor. The Minuet would then be repeated on the return of before a final cadence.