Form

It is a sectional form.

• A [a (measures 1-8) + b (measures 9-16)]
• A1 [a (measures 17-24) + b1 (measures 25-28)]
• Coda (measures 29-38)

Instructions, likely representing the title's "fog," such as "soft pedal throughout" and "As softly as possible," are found at the beginning.

The theme is constructed using the whole-tone scale. The first four measures of the theme resemble a cluster and lack harmonic function. However, in the subsequent measures, by forming a whole-tone scale, it is revealed that the opening cluster was based on the whole-tone scale.

Rather than tonality, the work evokes nuances of light and shadow and a sense of color, similar to what is found in Debussy's compositions.