These maps compare the possible routes of a one-kilometer walk in two neighborhoods in the Seattle area: the heavily cul-de-sac’d Woodinville and the gridded Ballard neighborhood. Cul-de-sacs (or, if we’re sticklers for French grammar in our loan-words, culs-de-sac, or if we’re actual French, les impasses) are designed, in part, to free residential suburbs from the noises and hazards of automobiles, with the side effect of making it nearly impossible to go anywhere without a car. I suppose a secondary effect of the culs was to mask the depersonalizing qualities of vast suburbs of near-identical houses all built over the course of a few months—again, at the depersonalizing cost of making coming and going by foot, bicycle, or public transit much more difficult. In an added layer of irony, the map on the right looks far more organic, almost lung-like, but (our shifting urban values tell us) the mathematical abstraction on the right is the one more suited to healthy city life. 
from “The Unintended Consequences of Cul-de-sacs,” by Ania Wieckowski, Harvard Business Review, May 2010 :: via The Infrasructuralist