The piece was then honed in Nieborów (October 1981), with the composer creating the first sketches for Three Psalms at the same time.

The programme booklet of the 1987 Poznań Music Spring featured the following commentary by the composer:

The piece consists of many slow, fast, lyrical and dramatic segments. Their sequence has nothing to do with the tradition of symphonic poems. The reminiscences consist in selecting certain ‘bundles of notes’ and rhythmic figures. The piano part plays a significant role, not only percussive (p. 95).

Mycielski’s composition, full of rhythmic freedom and surprising listeners with juxtapositions of dramaturgically diverse fragments, follows the genre principles of fantasia as a work of unspecified, individual structure, based on an assembly of particles. The material coherence indicated by the composer is manifested in returns of the alla zoppa rhythmic motif (presented in various configurations, including with the use of augmentation) and the characteristic melodic motifs (a pendular motif featuring steps of seconds and thirds, and a dissonant motif with a restless, even sharp rhythmic outline). 

Dramaturgically, Fantasia is full of contrasts – lyrical melodic lines, mostly entrusted to the string quintet, are interspersed with penetrating interventions from wind instruments, used in the full spectrum of sound. The work’s dissonant harmonic fabric heightens the impression the composer shared after the premiere: “I have never written anything so ominous” (Zygmunt Mycielski, Niby-dziennik ostatni 1981–1987, ISKRY, Warsaw 2012, p. 656).