" Reaching into her pack again, Ceony pulled out a simple bookmark, long and pointed at one end. She handed it to Zina.
Her sister crooked an eyebrow. “Uh, what is this?”
“A bookmark,” Ceony explained. “Just tell it the title of the book you’re reading and leave it on the nightstand. It will keep track of what page you’re on by itself.” She pointed to the center of the bookmark, where she’d overlaid a small square of paper. “The page number will appear here, in my handwriting. It should work for your sketchbooks, too.”
Zina snorted. “Weird. Thanks. "

― Charlie N. Holmberg , The Glass Magician (The Paper Magician, #2)