I composed this piece while experimenting with major and minor chords and the Dominant seventh chords. At that time I was looking for some colorful techniques that would sound rather modern and at the same time still could be appreciated by the untrained listeners.
As the title suggests, the Theme opens the cycle. It has simple four-part chordal texture and is best played with the Principal 8' stop. The harmonization is not based on the rules of Classical harmony, though. Surprise and colorfulness are very prevalent concepts here.
Variation 1 is a bicinium in 4/4 meter for two parts with a recurring melody - the Ritornello. The chorale tune is in the soprano, played by the 8' reed and the bass - with the 16' reed. In the video I use Oboe and Basson.
Variation 2 is a trio in 6/8 meter. The tune is in the lowest voice and this episode is best played on 8' and 4' flutes. This variation also has the Ritornello.
Variation 3 is a quartet in 3/4 meter with an eight-note motion and I recommend Principals 8', 4', and 2' for the registration. Chorale phrases are connected by the three-part Ritornello.
Variation 4 is a fast-paced Toccata with a simple sixteenth-note figure moving in one of the hands. It's very convenient for performer. The other hand takes the four-note 43 chords in parallel motion and plays the chorale tune.
As you can see, the first 3 variations are composed using Baroque techniques - popular meters and the Ritornello. But the harmonic language is far from Baroque. I use three-note major and minor chords (together with the dominant seventh chords and their inversions). Mostly they are built a minor or a major third apart (up or down) which gives quite a colorful feeling for the entire cycle (you can sense this right from the opening measures of the theme).
Before learning this piece, first try to understand the chords and their inversions. For this to happen, look at every beat, take the bass note and build the chord upwards in a closed position to see what kind of inversion this is. Make a mental note of what kind of interval is used between the chords in each case.