The narrator explains how inhabitants of Flatland determine direction and construct their homes in the absence of a visible sun or stars. A natural Law of Nature exerts a constant attraction toward the South, which serves as a reliable compass across most climates, supported by regular rainfall originating from the North. In towns and the countryside, the orientation of houses and tree trunks helps travelers navigate, though mild southern attraction in temperate regions can occasionally leave individuals stranded until the rain begins. This attraction affects older people and delicate females more intensely than the male sex, requiring polite gentlemen to yield the northern side of the street to ladies when passing.
Because light illuminates Flatland uniformly from all directions at all times without a known source, houses do not feature windows. Past scholarly investigations into the origin of light led to madness and were ultimately banned by the Legislature, leaving the narrator as a lonely holder of spatial truths who is mocked by compatriots. Consequently, domestic architecture follows specific standard designs focused on safety and community welfare.
The most common architectural shape for homes is the five sided pentagon, featuring northern walls that form a roof without doors, an eastern door for women, and a larger western door for men. Triangular and square houses are prohibited by law because their sharper angles present severe hazards to distracted travelers who might collide with them. While triangular dwellings were banned as early as the eleventh century except for military structures, square houses persisted under heavy taxation until later legislators restricted them in large towns to ensure public safety. Today, the pentagonal design has become the universal standard throughout both urban and rural areas.