Tempo, rhythm, pitch, harmony, instruments, melody, timbre, scale (96 kinds of 7-note scales for starters), mood, phrasing, mode, intensity, smooth, staccato, etc. In writing there are also variables, probably more kinds than in music. After all, there are only 12 notes, but 26 letters. What are the varibles in writing?
Language, font, grammar, strophe, rhythm, periods, character, scene, and your chapter, as well as breaks, paragraphs, conversation, situation, genre, narrative, description, purpose, footnotes, endnotes, etc. We expect change in writing or we wouldn't read far. It was highly amusing to find the German general speaking in pre-war Black Letter font in one of Umberto Eco's recent novels. Generally the situation, motif, is resolved very near the end, which is how you know you have reached the end. The reader will know if he has something by the end of the first page. Finis right there like a 3-minute pop tune if he finds it flat.
How very true. You have to grab and hold their attention with that first page to guarantee they turn to the second. It's crucial.