are conditioned to avoid basic interactions with strangers, especially those of a different income, race, or educational background, to the extent that they cannot imagine having a deep personal relationship with others so unlike themselves. This is a false choice on any bustling sidewalk, where everyone is afforded the same dignity, right of way, and incentive to interact without fear of compromising one's privacy or creating new personal obligations. In this way, suburban residents ironically tend to have less privacy in their social lives than their urban counterparts, in addition to a dramatically reduced volume of public acquaintances. Assimilating children Sidewalks are great places for children to play under the general supervision of parents and other natural proprietors of the street. More importantly, sidewalks are where children learn the "first fundamental of successful city life: People must take a modicum of public responsibility for each other even if they have no ties to each other." Over countless minor interactions, children absorb the fact that the sidewalk's natural proprietors are invested in their safety and well-being, even lacking ties of kinship, close friendship, or formal responsibility. This lesson cannot be institutionalized or replicated by hired help, as it is essentially an organic and informal responsibility. Jacobs states that sidewalks of thirty to thirty-five feet in width are ideal, capable of accommodating any demands for general play, trees to shade the activity, pedestrian circulation, adult public life, and even loitering. However, she admits that such width is a luxury in the era of the automobile, and finds solace that twenty-foot sidewalks – precluding rope jumping but still capable of lively mixed use – can still be found. Even if it lacks proper width, a sidewalk can be a compelling place for children to congregate and develop if the location is convenient and the streets are interesting. The role of parks Orthodox urbanism defines parks as "boons conferred on the deprived populations of cities." Jacobs challenges the reader to invert this relationship, and "consider city parks deprived places that need the boon of life and appreciation conferred on them." Parks become lively and successful for the same reason as sidewalks: "because of functional physical diversity among adjacent uses, and hence diversity among users and their schedules." Jacobs offers four tenets of good park design: intricacy (stimulating a variety of uses and repeat users), centering (a main crossroads, pausing point, or climax), access to