3-D is a gimmick film. Instead, Hitchcock was thinking about two young men from Chicago, Nathan Leopold and Richard Loeb. Hence, the boys invite the family, girlfriend, and friends of their ex-fraternity brother. The party begins, and the stage theatrical element of the film becomes of the utmost importance. For eight to ten minutes at a time, a full reel of film, there are no cuts in the action.
Life gets interesting.
The two men watch in delight as the guests squirm. No, no need to go in there. So the guests simmer as Jimmy Stewart begins to work his magic. Stewart unravels the entire plot with his cool and calculating philosophical training. Philip oozes guilt and attempts to hide his sputtering fear of this hyper-intelligent teacher.