One of the best places to understand specific design operations for a nimble urbanism is where churches – and their associated appendages (rectories and the like) – meet the historic residential fabric in Boston. In this example, on lower Mt. Vernon Street in Beacon Hill, the apsidal end of the Advent Church (that faces Brimmer Street) meets the end of a row of townhouses. In this case, the large scale of the apse is balanced by the almost-miniature scale of the girdle-like ambulatory at its base. This shift to a dollhouse scale means that the abutting townhouse is not overwhelmed by the overall mass of the church. Most satisfying is the negative space at the intersection – like something out of Scott Cohen’s studios at the GSD. Note the tiny bathroom window deep in the crotch – an amplified version of the scale-inversions that propel the entire composition.