The “B-A-C-H, Perpetuum Mobile”, composed in 2016, refers to a statement by Beethoven in which he expressed admiration for the infinite richness of Bach's musical art. The idea of infinity inspired Bernhard Klapprott (harpsichordist, organist, director of the Institute for Early Music at the University of Music in Weimar) to create his musical perpetuum mobile. Two harpsichords merge into a large, rich sound that builds from nothing on an ostinato up to fully notated clusters. In addition to the B-A-C-H motif, the entire work is based on the three intervals underlying this motif, which are heard in various constellations. Expansive arcs of tension evoked through rhythmic condensation, a gradual decrease in the number of parts while simultaneously shifting them to different pitches lend the work a sense of space and expansiveness. The dynamics are created by the movement itself, so that no changes of register are prescribed. The work emerges and fades away, ending as it began – the musical realisation of the idea of infinity.