Lichtenstein, a pioneer of postmodern recycling, swiped the subject of his mural from a beloved masterpiece of German painting — Oskar Schlemmer’s “Bauhaus Stairway,” of 1932, which is owned by the Museum of Modern Art. The painting depicts an actual staircase at the Bauhaus, the progressive art school that opened in Weimar, Germany, in 1919, and exemplified the modern movement at its most extroverted and techno-friendly. Artists claimed a bond with designers and engineers and set out to repair the world.