Alvin Kernan, The Playwright as Magician. New Haven: Yale University Press, 1979. pp. 102–103.
From time to time this submerged or latent theater in Hamlet becomes almost overt. It is close to the surface in Hamlet’s pretense of madness, the “antic disposition” he puts on to protect himself and prevent his antagonists from plucking out the heart of his mystery. It is even closer to the surface when Hamlet enters his mother’s room and holds up, side by side, the pictures of the two kings, Old Hamlet and Claudius, and proceeds to describe for her the true nature of the choice she has made, presenting truth by means of a show. Similarly, when he leaps into the open grave at Ophelia’s funeral, ranting in high heroic terms, he is acting out for Laertes, and perhaps for himself as well, the folly of excessive, melodramatic expressions of grief.
Almost all of Shakespeare’s Hamlet can be understood as a play about acting and the theater. For example, in Act 1, Hamlet pretends to be insane in order to make sure his enemies do not discover his mission to revenge his father’s murder. The theme is even more obvious when Hamlet compares the pictures of his mother’s two husbands to show her what a bad choice she has made, using their images to reveal the truth. Also, when he jumps into Ophelia’s grave, hurling his challenge to Laertes, Hamlet demonstrates the foolishness of exaggerated expressions of emotion.
"Almost nothing of Kernan’s original language remains in this rewritten paragraph. However, the key idea, the choice and order of the examples, and even the basic structure of the original sentences are all taken from the source. This is another clear example of plagiarism. When paraphrasing, it’s absolutely necessary (1) to use your own words and structure, and (2) to place a citation at the end of the paraphrase to acknowledge that the content is not original."
Source: Princeton University, http://www.princeton.edu/pr/pub/integrity/pages/plagiarism/