But there is a considerable increase in the subtlety with which the phrases are combined, in the “modelling,” so to speak, of the melody. Greater variety is perceptible, the balance of the phrases is less obvious, while equally satisfactory. The structure, in the more extended sense, is ternary.[29] The first section of Haydn’s Minuet, just cited, ends, after eighteen measures, in the dominant key. The second section, or section of contrast, contains some passages that are markedly different from the original theme, though congruous with it, and modulates so far afield as E-flat major (the home key being G). After twenty-two measures of this digression, the section of reassertion enters with the original theme in the tonic key, lasts twenty-two measures, and ends strongly in the home key. The minuet proper, as with Bach, is followed by a similar short piece, called the trio, put in for the sake of contrast. After it the minuet recurs; and it is an interesting fact that the whole movement is thus a large example of the same device of statement, contrast, and reassertion that is exemplified in its parts. In other words, the whole minuet is a “statement,” the whole trio a “contrast,” and the repeated minuet a “reassertion.” We see here, then, the fundamental form which we described as ternary, and which may be symbolised by the letters A B A, utilized as a structural agent both in the individual parts, and in the whole of the movement. The symphonic minuet is quite obviously the child of the suite minuet, but a child approaching maturity, becoming complex and intricate in coordination. The form generally adopted for the last movement of sonatas exemplifies a different way of utilizing the same general principles of design. As its name of “rondo” implies, it consists of a constant recurrence or “coming around” of the main thematic idea, which, as before, we may call A; but with several contrasting sections, instead of only one. The rondo type of structure may be symbolized by the letters A B A C A D A, etc. It embodies, obviously enough, a greater variety than the simpler dance form out of which it grew, and at the same time preserves unity by the repetition of the main theme. It is less perfectly coordinated, however, than the minuet; for as each episode occurs but once there is a deficiency of logic and of artistic economy; and as the principle of the form is sectional there is no intrinsic reason why it should not be prolonged indefinitely. It is, therefore, an essentially imperfect and indeterminate organism, although it is serviceable enough as the mould of a movement in which gaiety and general animation are more important than highly articulated plastic beauty.