Brahms's Piano Sonata in F-sharp Minor—his opus 2, but composed before opus 1—begins with a splash (see ex. 7.1). A splattering arpeggio ripples up the keyboard; its force (Brahms marks it energico) rebounds into rising melodic octaves whose surge is abruptly halted, as if hitting a wall. Another splash and another surge brings another lurching slap against that wall— and this time an even greater swell rises up, slowly gathering force, hitting its registral peak and cascading downward to crash against the rock of the opening arpeggio once more.

More technically: the opening tonic chord secures the downbeat, the upward arpeggiando providing the hint of an upbeat to the staccato-wedged top note. There follow rising thirds in octaves, but those thirds cut across notated beats; the meter remains unclear until the sudden accent on beat 3. Thus only beats one and three are clearly articulated; in between is only energetic forward impulse. The second measure sequentially repeats the first but on III, initiating an apparent sentence structure. The third leg of that sentence, on V, is cast differently: above a tremolando bass, agitated two-note figures rise higher and higher. The continuous motion has now fully obscured the beat level: we hear only forward impulse, nearly ametrically. The peak D (an implied ninth above the still-assumed dominant seventh) resumes the octave doublings and gives weight to a notated downbeat (m. 7), but the chromatic cascade downward moves relentlessly past any metric markers. Only at the poco ritardando is there a containment of this motion (both in the marking and in the slowing of downward motion by alternating the chromatic steps and the repeated C♯s; see measure 8), suggesting a half cadence might be at hand. Too late: the forward impulse cannot be curtailed and the phrase overflows into its repetition (m. 9), creating an elision. Its energy is contained only by the return of the opening's articulated downbeat; the counterstatement manages a stop on V only through a lurching (written-out) decelerando (see ex. 7.1 above).

These two passes through this powerful opening sharpen our awareness of how music moves through time, and the metaphors we find useful to describe that awareness.