Intertextuality is the “visual referencing between films”, where a film will ‘borrow’ ideas, effects or certain aspects from a scene, from another film. They usually use the same editing techniques, camera shots and mise en scene.
Aspects from the bathroom scene in the movie ‘psycho’ are commonly used in other films like what lies beneath and fatal attraction. The typical ‘white’ bathroom with white tiles, bathtub and shower curtains, the sound of running water, the high angle shot of the bathroom, the shower curtains falling onto the dead body and even the murderer using a similarly shaped knife are all forms of Intertextuality deriving from ‘Psycho’.
(Here is the famous bathroom scene from the movie 'psycho')