Poland has had a complicated history, and the country’s artists have sometimes struggled to craft a true national identity. A new show in Chicago traces the 20th century history of Polish art, especially as it involves the migration of Polish artists to Paris. “Factors contributing to identity also changed, so that at the start of the exhibition looking to Western Europe was progressive whereas at the end it was thought to interfere with national allegiance. But this makes the show more interesting rather than less.”