Massachusetts-based NS Builders works on expensive custom homes. This bathroom space brings a unique challenge: Because of the sink's location, there's no way to put a mirror over it without having to cover up the window.The clever solution adds both mirrors and medicine cabinets: It took a team to make this happen: This was designed by Brooklyn-based architecture firm Of Possible, the cabinets and millwork are by Philadelphia-based Robern and Massachusetts-based Materia Millwork, and NS Builders executed the build.