Gradus begins with a simple five-note ascending motif that is quickly manipulated and developed by interjecting 8th rests and changing the order of the notes. After introducing the original 5-note set, Glass uses a kind of intuitive additive process, gradually adding notes one at a time over long stretches of music, eventually showing the complete set of 11 notes at the peak of the expansion in Part II. Immediately after the introduction of the complete set, however, the listener is hit with a 2-note motif of a major second, with four 8th notes tied together in two pairs, sounding like two quarter notes. This motif instantly spreads like a virus, sucking the moving 8th notes into itself, growing in rhythmic length as the set of notes instantly retracts. Eventually the motif itself is reduced to one single repeated note, sounding incessantly in the same rhythmic blocks we have heard throughout the piece, melody reduced to rhythm.
Listening to this music may require a change of perspective in the listener, as there isn’t any harmony or true melody in the traditional sense. Instead, what we have is a constantly evolving rhythmic and motivic flow, with many different characters brought out by the constant shifting of notes and rhythms. Imagine something like a black and white kaleidoscope that gradually unveils more shades of grey in constantly shifting patterns as you turn it, eventually giving way to twisting intricate shapes of whiteness.