wherein Grace becomes Dominique... Simply, one can define the monster of Sisters as women's liberation." The prominent allusions to works by Alfred Hitchcock have also been noted by critics such as Bruce Kawin, who wrote in 2000: Production Development De Palma was inspired to write the screenplay for Sisters after reading an article in Life magazine in 1966 about the lives of the Soviet conjoined twins Masha and Dasha Krivoshlyapova: The script, which De Palma co-wrote with Louisa Rose, features structural elements inspired by Hitchcock, such as killing off a prominent character early into the film, alternating points of view, and the involvement of a third party observer in solving a crime. In writing the exposition of the film which details the twins' history and institutionalization, De Palma was influenced by Roman Polanski's Rosemary's Baby (1968), specifically the scene in which Rosemary is raped and conceives her child. Filming Sisters was shot over a period of eight weeks in New York City in spring 1972, primarily in the borough of Staten Island. The apartment interiors were filmed on a set, with additional exterior photography of the Time-Life Building in Manhattan. The film was shot using Mitchell BNC cameras with Panavision lenses. According to De Palma, the film was lit with a "truly classical style", with scenes sometimes taking 45 minutes to set up. Some sequences were shot on 16 mm film by De Palma himself, such as the scene in which Emil speaks directly to the camera during the finale's hallucination sequence. Visual style The film uses unusual point of view shots and split screen effects to show two events happening simultaneously, as well as long tracking shots, some in excess of six minutes in length. The extended tracking shot in Danielle's apartment following the murder of Phillip was influenced by Max Ophüls and directly references Hitchcock's Rope. The theme of voyeurism is represented in the alternating points-of-view and distortions of perspective within the narrative diegesis; De Palma commented: "I really got the idea from watching the Vietnam war on television watching a war that nobody really knew about except that we watched it every night on the 7 o'clock news. It was really a very voyeuristic war, and I think it says a lot about the way we perceive things. We are very much controlled by the media which present things to us. And those can be manipulated." In