I have been practicing scales on the piano for a week now, and it has made a world of difference in the way I think about playing the piano. After my scales, to which I have now added scales in thirds, I treat myself to a new look at Mozart and Haydn sonatas. I can't help but notice that they are filled with scales, and since I have been practicing my scales, I can play the scale passages. I actually look forward to playing the scale passages, and feel very proud that I can play them fluidly.
It occurred to me this morning that perhaps Mozart wrote some of his piano sonatas to reward pianists who practiced their scales. It also occurred to me that the mid-18th-century piano sonata was not unlike an application or a game for a particular type of computer-based machine. Perhaps Haydn was kind of like a really clever software developer, thinking of ways to amuse and entertain his solitary users.