The Viennese music publisher Anton Diabelli—the first to publish a then-unknown Franz Schubert—was a trained composer and savvy businessman. Hoping to produce a best-seller for the home music market, he wrote a short waltz and sent it to every composer he could think of, asking for a single variation from each. Then Beethoven weighed in, with a massive set of 33 Variations: a rollicking explosion of creativity, his last major piano composition, and a comic masterpiece. Brian Connelly plays this merry juggernaut on Context’s world-class Vaughn Graf piano from 1826.