Next comes the “Free Fantasia” or “Working Out,” the section of contrast, derived from the similar section in the minuet, but far longer and more intricate. In material it is a development, or manipulation, of the thematic germs stated in the exposition, by aid of all the devices for developing motifs that we have traced. Structurally, its function is to establish complete contrast, to do away with the impression of rigid system that the first section is likely to engender, and in every possible way to give variety, surprise, and interest to the musical tissue. It is accordingly absolutely free in modulation, unsystematic in arrangement, and irregular in metrical division. In it the composer gives rein to his fancy, obeys the impulse of the moment, and lets his ingenuity rather than his shaping instinct determine his progress. Yet the section of contrast is not a mere limbo of chaotic impulses. It must have its own logic, it must be a true “development,” it must be throughout obviously founded on the themes already stated. There is no part of the sonata-form in which all the composer’s strength is more taxed than the Free Fantasia; here, indeed, freedom brings its own heavy responsibility. After the contrast comes the reassertion, or “Reprise.” Having displayed his materials in every light his imagination can suggest, and having meanwhile almost obliterated his hearer’s sense of the key of the piece, the composer now carefully prepares to gather up all his flying threads, to stamp all this baffling variety with ultimate unity. Re-entering the home key, which has gained by its long silence a new power to delight and satisfy, he restates his two subjects or themes, in their original guise, but now both in the home key. As the essayist, after all his examples and figures and metaphors, returns to a bald, emphatic, final assertion of his thesis, the composer now, after all his playing with his ideas, reinstates them in more than their primitive simplicity.[30] To give them perfect finality he even reiterates them with fresh assertiveness, seems unwilling to leave them, and insists, in his Coda or tail-piece, that we take away with us a full sense of their import. Thus restatement, emphatic and prolonged, following upon contrast and digression, completes the unity of the whole composition, and closes the cycle to our satisfaction. It is impossible to conceive a type of musical structure which should better satisfy our demand for profusion of detail together with clarity of fundamental shape, than this highly perfected product of a long evolution, sonata-form.