J.S. Bach - Prelude in C Major
Musically, the structural regularities of the Well-Tempered Clavier encompass an extraordinarily wide range of styles, more so than most pieces in the literature.The Preludes are formally free, although many individual numbers exhibit typical Baroque melodic forms, often coupled to an extended free coda (e.g. Book I preludes in C minor, D major, and B-flat major).
The Preludes are notable also for their odd or irregular numbers of measures, both as to phrases and as to the entire length of a given Prelude.
Each fugue is marked with the number of voices, from two to five. Most are three- and four-voiced fugues, and there are only two five-voiced (BWV 849 and 867) and one two-voiced (BWV 855) fugues. The fugues employ a full range of contrapuntal devices (fugal exposition, thematic inversion, stretto, etc.), but are generally more compact than Bach's fugues for organ.