The planned homogeneity of the Lisbons' suburb, with its evenly spaced houses, lawns, and elm trees, reflects the homogenized happiness of its inhabitants. When this happiness is challenged, there is a corresponding change in physical environment. As the Lisbon family's situation begins to decline, their house also falls into disarray, first internally and then visibly such that the neighbors and local media begin to take notice. More broadly, however, the environment continually influences its inhabitants and vice versa. The strength of environment's influence is demonstrated by the Lisbon sisters' remarkable transformation on the night of Homecoming, when they become radiant and normal upon leaving their house. By contrast, the strength of the inhabitants' influence on the environment is demonstrated by the neighborhood's rapid physical decline following the Lisbon sisters' deaths.
The novel's continual and explicit use of foreshadowing reflects its overriding sense of tragic fate. The deaths of the Lisbon girls are announced in the book's title and first sentence and then continually deferred, leaving the reader to wait in morbid anticipation. As the Lisbon sisters are introduced at Cecilia's party, the narrators mention their eventual means of suicide. Superlative remarks take on a sinister quality, like when Mary calls Homecoming "the best time of my life." More generally, the homologous structure of the book's events serves to subtly influence the reader's expectations of a scene. The boys' trip to the Lisbon basement on the night of Cecilia's party implicitly suggests their same descent, a year later, on the night of the girls' suicides. Likewise, Lux's post as lookout on Homecoming night echoes her post as lookout on the night of June 15. Finally, characters other than the narrators occasionally also make tragic or prophetic remarks. Old Mrs. Karafilis is thought to have sympathized with the girls in their view of death, the cemetery workers go on strike with the first suicide, and Dr. Hornicker warns of a high incidence of repetitive suicide in families.
Reflecting its concern with the limits of knowledge, memory, and vision, the novel continually invokes these limits through symbolic use of physical boundaries. The boys' failure to see or enter into the interior of the Lisbon house reflects their inability to understand the girls' lives or thoughts. Likewise, Lux's regular appearance in doorways and windows and on thresholds symbolizes her role as an intermediary between the boys and her sisters. The neighbors are upset when the Lisbons' unraked leaves blow onto their lawns, symbolizing that the disarray of the Lisbon house is exceeding its acceptable bounds. Most dramatically, Cecilia's jump onto the fence shortly after having begun to menstruate symbolizes that she is permanently stuck on the boundary between childhood and adulthood.