Konrad Klapheck is a German pop-art/surrealist painter, favoring "ironic treatment of everyday mechanics." Below is some of his machine-focused work. I would imagine that the marching hammers in Pink Floyd's "The Wall" were inspired by Klapheck's paintings.
Konrad Klapheck, Das Opfer (The Victim), 1989
Konrad Klapheck, Der Krieg (War), 1965
Konrad Klapheck, Die Fanatikerin (The Fanatic), 1979
Konrad Klapheck, no info
Konrad Klapheck, Der Mütterliche Vater (The Mother's Father), 1977