During their investigation of Keith’s mother’s desk, Stephen and Keith examine her diary and find tiny X marks on specific days in her calendar. They find a pattern in the “X’s,” which occur once a month and are sometimes “crossed out and entered a day or two earlier or later.” The boys discover that the “X’s” coincide with the new moon and they assume it as a mark for her secret meetings, though the reader may comically realize that the “X’s” probably record her menstrual cycles. Later in the novel, the boys also find a package of cigarettes marked with an “X” in a tin box that further kindles their imaginations. Therefore, the letter “X” symbolizes the unknown and the flexibility with which it allows anyone to attach varied meanings to it. Throughout the novel, Stephen obsesses over the meaning of the X’s, and he considers their wide potential to symbolize a kiss, a mathematical variable, Auntie Dee’s hypothetical boyfriend, and eventually, the mysterious man that Keith’s mother is taking care of and keeping in hiding. In essence, “X” speaks to the novel’s larger theme of imagination through the infinite possibilities of meanings that it can harbor.
The timeline below shows where the symbol The Letter “X” appears in Spies. The colored dots and icons indicate which themes are associated with that appearance.
...was “revising” in various school subjects. Then Stephen’s father asks him to solve the equation 7x^2 = 63, but Stephen is distracted by the moon outside, thinking of Keith’s mother’s “x”... (full context)
...the puzzle: he thinks Keith’s mother isn’t a spy, but is instead taking care of “x,” a German airman who was shot down. Stephen imagines the airman parachuting down, Keith’s mother... (full context)