Hayes includes Wanda Coleman’s definition of an American sonnet in American Sonnets for My Past and Future Assassin, acknowledging her form as a model. Coleman’s and Hayes’s American sonnets maintain the standard 14 lines of traditional sonnets, but use internal rhyme and alliteration rather than end rhymes to knit together the poem’s music: Coleman related her sonnets to jazz improvisation. In “Probably twilight…,” Hayes avoids typical end rhymes, in favor of repeating end words: “happened” or “happens” ends lines 4, 6, and 7, while “encounters” ends 2 and 9. Lines 3 and 8 end rhyme with “say” and “day.” Lines 11-13 end in assonance and repetition: “blackness” repeats bl, k, and s sounds in “dark blue skin.”

Hayes’s American sonnet makes strong use of the traditional sonnet's volta, or abrupt shift in meaning or perspective after the first eight lines. In “Probably twilight...,” in line 9 Hayes’s speaker turns more directly to the audience—the reader or the assassin—for the last six lines, the sestet.