Perpetuum mobile

In music, perpetuum mobile (English pronunciation /pərˌpɛtjʊəm ˈmoʊbɪleɪ/, /ˈmoʊbɪli/; Latin, literally, "perpetual motion"), moto perpetuo (Italian), mouvement perpétuel (French), movimento perpétuo (Portuguese) movimiento perpetuo (Spanish), is a term used to describe a rapidly executed and persistently maintained figuration, usually of notes of equal length.

Over time it has taken on two distinct applications: 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 second, 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.

Some of the riddle canons of Bach's Das Musikalische Opfer are examples of this particular kind of perpetuum mobile/canon perpetuus.

[citation needed] 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.