Perpetuum mobile (Latin), moto perpetuo (Italian), mouvement perpetuel (French), literally meaning "perpetual motion", means two distinct things:

1. Pieces of music, or parts of pieces, characterized by a continuous steady stream of notes, usually at a rapid tempo.

2. Whole pieces, or large parts of pieces, which are to be played repeatedly, often an indefinite number of times.

Even though everything is notated using musical notation, the music is sort of one long loop. The ostinato repeats with developing material above.

This 7th of seven 'mobiles' features syncopation, complex string pizzicati, with solo woodwind lines that accumulate overtop and a lopsided 7/8 time signature.

Syncopation: a temporary displacement of the regular metrical accent in music caused typically by stressing the weak beat.

Pizzicato: a playing technique that involves plucking the strings of a string instrument.

Ostinato: a continually repeated musical phrase or rhythm.

7/8 time: seven beats in a measure, with each 8th note getting a beat.

Instrumentation: Piccolo, 2 Flutes, Oboe, English Horn in F, E-Flat Clarinet, 2 B-Flat Clarinets, B-Flat Bass Clarinet, 2 Bassoons, Contrabassoon, 4 French Horns in F, Trombone, Timpani(4), Orchestral Crash Cymbals, Snare Drum, Bass Drum, Violin I, Violin II, Violas, Violoncello, Double Basses