Hans Arp was a founding member of the Dada movement, whose practice emphasized spontaneity and chance. The Dada spirit continued to inform his entire artistic production, and he defended “concrete” art (a term he preferred to “abstract” art), which he associated with a social purpose: “Concrete art is an elementary, natural, healthy art that plants the stars of peace, love and poetry in the spirit and in the heart.” With their biomorphic and undulating forms, many of Arp’s sculptures seem to defy gravity and often suggest movement: the curved bottom of this work actually permits it to rock back and forth, as its title suggests.