The remaining movements of the sonatas expanded under the same powerful imagination. Let one compare the variations which form the slow movement of opus 10, No. 2, with those in the slow movement of opus 106, or those which constitute the second and last movement of the last sonata. In these later variations we find something of the same change of the theme into various metaphors as that found in the Goldberg Variations of Bach. It is not so much an idea adorned as an idea expanded into countless new ideas. The variations written for the publisher Diabelli on a waltz theme are indeed exactly comparable to those of Bach. To slow movements in song form or in triplex form he appended the codas in the nature of an epilogue which added so much to the first movements. The adagio of opus 10, No. 3, offers a fine example. Frequently the slow movement led without pause into the next, more frequently than in the sonatas of his predecessors. The rondo took on a weight and significance to which it was scarcely considered sufficient by the older masters. The rondo which is the last movement of opus 53 is of huge proportions. Beethoven frequently composed his sonatas in four movements, following in this the model offered by the symphonies of his predecessors. The added movement was descended from the minuet. In some of the sonatas it still bears the name and occupies its traditional place between the slow movement and the last movement, notably in the sonatas opus 2, No. 1, and opus 10, No. 3. In opus 2, No. 2, and opus 2, No. 3, the movement is called a scherzo and has lost not its dance rhythm but its dance character. In opus 31, No. 3, the scherzo has not even the triple rhythm which usually distinguished it. It follows the first movement and is itself followed by a minuet and a final rondo. In 106 it is again the second movement, and in 110 can be recognized in spirit, without a name, likewise as second movement. The scherzos introduce into the later sonatas, as into the symphonies, a note of something between irony and mystery, a strange development from the sunny dances of Haydn; a sort of harsh echo of life in dense valleys from which Beethoven has long since ascended. And finally the fugue finds place in the scheme, sounding invariably a note of triumph, as of the power of man’s will and the immutable law of order in the universe. Thus by extending the length of the various movements, by adding distinct and significant themes in transitional and closing sections of the triplex form, by incorporating additional movements in the sonata group, by introducing forms like the scherzo and the fugue, which, though they had been found in the suite, had been almost never employed by the composers of sonatas, Beethoven enormously expanded the sonata as a whole. But even more remarkable was the tendency which showed itself relatively early to give a unity and coherence to the group.