Cyclical repetition is deeply important to this poetry collection, in which 70 poems share the same title, and each begins with the last line of the previous sonnet in the sequence. The sonnets form a body of work linked by title, by their shared lines, and by the fact that their first lines form yet more sonnets when read in the index—repetition that expands their meanings.

Within “Probably twilight…,” several words and phrases repeat verbatim: “probably” (Lines 1, 2, 9, 11, 12), “something happened” (Lines 4, 5, 6). Others recur with slight alterations: “all my encounters” (Line 2) becomes “all of our encounters” (Line 9), while “Probably twilight makes blackness dangerous / Darkness” (Lines 1-2) becomes “Probably twilight makes blackness / Darkness” (Lines 11-12). “Dark blue skin” repeats, along with “matches” in lines 12 through 14. It’s almost more noteworthy to examine the words that do not repeat or echo: “You won’t admit it” (Line 10).

Hayes uses forms and images related to return and repetition to underscore the theme of chronic violence and anxiety. The poem's shared title, "American Sonnet for My Past and Future Assassin," refers to an eternal loop that repeats in the “past” and “future.