In the 1950s, the German artist Gerhard Richter was struck by four photographs secretly taken at Auschwitz, outside the dreaded death facility Birkenau. The images showed corpses on the ground, some still smoldering, while Nazi guards chatted. In 2008, looking through a new book, Richter saw the photographs once more and could not look away. In 2014, he projected the lines of these four photographs onto canvas, began painting, and realized, he has said, “that it wasn’t working at all. So I scraped it off and painted again until I had four abstract images. It’s not unusual for me to start from the figurative and end up with something abstract.” The four works are black, white, gray, with shots of blood red and forest green. The dark engine remains. —E.C.