Walking through this exhibition of some 250 works by nearly a hundred artists working in the former Eastern Bloc, I was forced at one point to turn back and re-enter it through the exit so that a mess left by a “service” dog could be cleaned up. Doubling back to go forward was an apt metaphor, I thought, for the frequent adjustments to circumstances that these artists working either unofficially or within the “second public sphere” had to perform throughout the period covered by this major historical overview. Indeed, one of the biggest accomplishments of a show covering six former countries that constitute nine present-day ones (Poland, Romania, Hungary, the former East Germany, Czechoslovakia, and Yugoslavia) is that it conveys the complex lived reality of artists who, while making work for the same multifaceted reasons as their peers elsewhere in the world, were constrained by various degrees of state hostility during a series of asynchronous national “thaws” and “freezes” imposed by the Soviet “brother.” The exhibition is noteworthy for how much it tries to accomplish and the possibilities for discovery it offers, with works ranging from heartbreaking to whimsical. Organized into four large sections, it covers the themes of “Public …