What is defensive structure?

Famous quotes containing the words structure and/or defensive:

    If rightly made, a boat would be a sort of amphibious animal, a creature of two elements, related by one half its structure to some swift and shapely fish, and by the other to some strong-winged and graceful bird.
    Henry David Thoreau (1817–1862)

    Stay-at-home mothers, . . . their self-esteem constantly assaulted, . . . are ever more fervently concerned that their offspring turn out better so they won’t have to stoop to say “I told you so.” Working mothers, . . . their self-esteem corroded by guilt, . . . are praying their kids turn out functional so they can stop being defensive and apologetic and instead assert “See? I did do it all.”
    Melinda M. Marshall (20th century)