Ma?gorzata Mirga-Tas is the sort of person who hugs a visitor even before she says hello. She welcomes me into her home in the village of Czarna Góra, at the foot of the Tatra mountains in southern Poland, with a high-wattage smile. The artist’s house is right next to her aunt’s and her mother’s. The modern buildings huddle together, facing each other protectively round a flower garden. Mirga-Tas loves being close to so much of her family. “I go out of my house,” she says, “and drink coffee with my mother and my sister before I go to work.” This...