Right. Cracks on the shell. Kate remembered studying those during the last lesson. There were five different cracks they'd studied, if she remembered correctly. She tried to go over all of them in her head, but as her classmates started sharing their own answers, Kate's line of thinking kept getting interrupted. She was trying to come up with something that hadn't been said, but with everyone else sharing answers, too, she couldn't remember what had been said and what hadn't.

"What about a crack that goes straight downward?" she asked, raising her hand. "It means negativity and sadness." Speaking of which, how were you supposed to tell if the crack started up top and moved downward, or if started at the bottom and moved upward? Because, both of those meant two different things.