Hejinian 34: "Composition is a critical existential presence for Stein"
See her first public lecture, "Composition as Explanation" (1926)
in part about "the business of life"; "the process of living"; "everyday habits" as well as "the being of individaulity" (all phrases, I believe, are Hejinian's)
in part about Flaubert and Cezanne
Stein: "Cezanne conceived the idea that in composition one thing was as important as another thing"
see also The Making of Americans, completed around this time? [published 1925, per Wikipedia, though "put aside" nearly "a quarter of a century earlier," per Hejinian]