After World War I broke out, Picabia became fascinated with the idea of industrial objects as a pictorial source. He once wrote that "the machine has become more than a mere adjunct of life. It is really a part of human life...perhaps the very soul...I have enlisted the machinery of the modern world, and introduced it into my studio." His goal, he said, was to invent a "mechanical symbolism," and this piece is one of his most important examples, since critics have read it as an image of a sexual act rendered in mechanical terms. Although, at first glance, it might be hard to read in these terms, Picabia may well have been inspired by his friend Marcel Duchamp to bury sexual references in images of machines. This work is also significant in that it is Picabia's first known collage (hence, as the title suggests, "very rare") since it contains two mounted wooden forms, and the frame is integral to the piece. - See more at: http://www.theartstory.org/artist-picabia-francis.htm#sthash.xchIYynP.dpuf