Director and producer Alfred Hitchcock’s 1948 masterpiece, “Rope,” begins deceptively, with fine lilting music and scenes of an idyllic New York City block. A woman walks her baby in a stroller, a car glides down a one-way street, and a policeman escorts two boys through the light traffic. Despite omnipresent brick, glass, and concrete, the view is almost bizarrely pastoral. Then as the credits finish, a fierce scream is heard, but all too briefly. The scene changes and two young men in a plush Manhattan apartment are strangling a third. “Strangulation has more vivid pictorial qualities,” Hitchcock explained in macabre detail. “It is considerably more horrifying to watch a man struggle and strain under the agonizing pressure of an effective throttling, than to see one slump and flow with bullets in his midriff or a shiv between his ribs.” Their task completed, the two young men stuff the dead body …