Back in the 18th-century when this Massachusetts farmhouse was built, there was no such thing as a master bath. So architect Michael T. Gray and interior designer Hattie Holland, both of Carpenter & MacNeille, carved one out of a hallway and added wainscoting and window casings to create a sense of the past. Painted a deep blue-gray, they stand out against the pale blue walls. The color "has a historic feeling with that gray cast and plays off the Carrara marble so well," Holland says. In the center of the floor, a virtual rug made of marble in a basket-weave pattern adds another layer of detail to the room.