According to critic Stephen Rupp, Calderon creates in his play, La vida es sueno (or Life is a Dream) "a process of repetition which creates thematic and narrative patterns and generates a space of delay in which the reader may apprehend those patterns as central to a fitting closure" (292).
While reading Life is a Dream, I did take time to bust out my handy dandy highlighter and greenify several repeating words and phrases in the play. Thus, Rupp's analysis seems correct. Calderon's use of repetition did cause me to "apprehend those patterns" and note their importance to the text as a whole. For example, the very first word I highlighted was the second one spoken: "Hippogriff." While I didn't know this at the time, I would continue highlighting references to "animals" and "beasts" and "labyrinths" throughout the play. (In case you're confused as to why I lump "labyrinth" in with references to "beasts" see this site on the myth of the Minotaur in greek mythology. I plan on using this in my project so, I won't go into too much detail on this connection here.) Further examples of repetition lie in the repeated references to the play's title, continuous references to the sun and other light forms (stars, candles, etc), descriptions of life as a state of "living death," and repeated references to the conflict between free will and fate. Calderon's repeated references to all of these thematic elements solidify their importance in the readers mind, allowing his audience to gain a better grasp on the possible messages he is implying, and thus enabling them to enjoy them further.