ABSTRACT
Compose the first few measures of four different two-part inventions, based on motive and based on theme. The fifteen keyboard inventions of Johann Sebastian Bach are a treasure trove of compositional techniques. Bach's approach to the works is highly imaginative. Some of the inventions are constructed from a simple motive, some from a compound motive. Others are based on a longer theme, several on a double theme: two melodies heard simultaneously. Four of them are closely related to fugue, one is a series of canons, and two have affinities with what came to be known as sonata form. The inventions in which a more extended theme forms the basis of the composition are, in fact, no less motivic than those that stem from a simple short motive. The reason is that the theme itself, whether two, three, or four measures in length, is made up of shorter motives that tend to proceed according to the principle of pattern-sequence-contrast.
