How does the author use foreshadowing in The Book of Laughter and Forgetting?

Although a simple, revolutionary poem at the time, Mama's poem takes on new meaning when she tries to recite it to her son and daughter-in-law, Marketa. She cannot remember the final stanza and gets confused as to when she recited it the first time. For this reason, the poem comes to represent her past and how her memories are failing her: it also foreshadows her ultimite mental demise.