In music, perpetuum mobile (English pronunciation /pərˌpɛtjʊəm ˈmoʊbɪleɪ/, /ˈmoʊbɪli/; literally, "perpetual motion"), moto perpetuo (Italian), mouvement perpétuel (French), movimento perpétuo (Portuguese) movimiento perpetuo (Spanish), carries two distinct meanings: first, as describing entire musical compositions or passages within them that are characterised by a continuous stream of notes, usually but not always at a rapid tempo; and also as describing entire compositions, or extended passages within them that are meant to be played in a repetitious fashion, often an indefinite number of times. Types of perpetuum mobile composition As a distinct composition, perpetuum mobile can be defined as one in which part or most of the piece is intended to be repeated an often unspecified number of times, without the "motion" of the melody being halted when a repeat begins. Canons are often intended to be performed in a moto perpetuo fashion, and can thus be called canon perpetuus. In some cases the repeats of a "perpetuum mobile" piece are at a different pitch, a modulation or a chord progression occurs during the repeatable part. Some of the riddle canons of Bach's are examples of this particular kind of perpetuum mobile/canon perpetuus. Perpetuum mobile as a genre of separate musical compositions was at the height of its popularity by the end of the 19th century. Such pieces would often be performed as virtuoso encores, in some cases increasing the tempo along the repeats. Examples Perpetuum mobile pieces of both kinds include: Baroque period The Preludio from Bach's Partita for Violin No. 3 consists almost entirely of sixteenth notes. Classical period The finale of Haydn's String Quartet No. 53 in D major ("The Lark"), Op. 64, No. 5 The finale of Beethoven's 22nd piano sonata, and large segments of the finales of his Tempest and Appassionata sonatas (although these are not very fast; the Tempest and the 22nd sonata are only marked Allegretto, and the Appassionata is marked Allegro ma non troppo) The second of Franz Schubert's Impromptus, D. 899 The fourth of Franz Schubert's moments musicaux (likewise not very fast, marked Moderato) Romantic period The finale of Carl Maria von Weber's Piano Sonata No. 1 Charles-Valentin Alkan's Le chemin de fer, op. 27, for piano Felix Mendelssohn's Perpetuum mobile, op. 119, for piano Ottokar Novacek's Perpetuum Mobile, for violin and piano Nicolò Paganini's Moto perpetuo Op. 11 (No. 6) for violin Nikolai Rimsky-Korsakov's Flight of the Bumblebee, an interlude for his