- "He [Marty] turned over the piece of paper on which Jennifer had written her note. It was the flyer given to them by the lady for the 1985 clock tower preservation campaign. At the very top of the sheet was a replica of the 1955 newspaper headline which read: CLOCK TOWER STRUCK BY LIGHTNING. CLOCK STOPPED AT 10:04. / Underneath was the date: Sunday, November 13, 1955."
- —From Back to the Future by George Gipe (quote, page 134)
Xerox was a manufacturer of photocopying machines which created copies of printed material, and also referred to copies made by such machines.
One of these copies — on blue paper — was given to Marty McFly, which was used as a handy piece of scratch paper by his girlfriend Jennifer Parker to write down her grandma's telephone number for Marty, along with a personal message (I love you!).
When Marty was stranded in 1955, the xeroxed flyer was used by Dr. Emmett Brown to predict the time and location of a lightning bolt that would generate the 1.21 jigowatts for another temporal displacement to send his older counterpart's DeLorean time machine back to 1985.