A monumental, aerial sculpture is suspended over Boston’s Rose Kennedy Greenway as the signature contemporary art installation in the Greenway Conservancy’s Public Art Program. Created by Janet Echelman, the sculpture spans the void where an elevated highway once split downtown from its waterfront and was made by hand-splicing 100 miles of rope and knotting twine into an interconnected mesh of more than a half-million nodes. I had occasion to enjoy it while I was downtown attending a design and manufacturing trade show being held at the convention center.