"Music of the classical and pre-classical periods is the language of ideas and gestures. Musical gesture becomes intelligible by recurrence and recognition. Turning an idea on one’s tongue, trying it out in slightly different wording, with a new intonation and in a changed voice creates the musical discourse - the story told, or the argument held. This is the definition of variation, and variation lies at the heart of musical expression. The sonata form is sometimes considered nowadays as the greatest achievement of musical thought of that period, but composers of the 18th century were happy to turn to more humble forms. Of these, Variations and Fantasias are probably those with the most distinguished histories. In Variations, an idea is confined to the simplest frame of a musical period, unable to break its own formal boundaries, but free to mutate in all possible ways inside them; in the Fantasia, a musical thought is born, develops and flourishes with no seeming restraint, but for the free will of the composer to structure this flow, and yet, they have in common this constant tension between the urge to repeat an idea and the necessity of altering, transforming it. This hidden conflict feeds creativity and the imagination: it generates, ultimately, the classical style."