If all had gone according to plan, construction cranes would hover above San Francisco, erecting towers where no towers had gone before.  Instead, we'll be contemplating a much different scene: a life-size reminder that skylines are like cities - they grow in fits and starts, and never  according to plan.  Viewed from this perspective, San Francisco's four newest and tallest condominium towers aren't simply shafts that scrape the sky...more.