 Often, though not always, the last measure or measures of the exposition are slightly different between the repeats, one to point back to the tonic, where the exposition began, and the second to point towards the development.In general, the "Development" starts in the same key as the exposition ended, and may move through many different keys during its course.It will usually consist of one or more themes from the exposition altered and on occasion juxtaposed and may include new material or themes—though exactly what is acceptable practice is a point of contention.