Look to the chapter titled "Hieroglyphics" for this answer. It is chapter 14. At the beginning of the chapter, Toby suggests that they have a hieroglyphic system. His notion is that it will give them a written code to communicate about the Egypt Game while at school. Each kid will also have his/her own symbol that identifies them. Other than April, the other kids think the idea is quite interesting. April thinks the idea is "crummy," but that is because she can't think of a cool Egyptian name and symbol. Suddenly she remembers the "sort of cat goddess," Bastet. The statue of Bastet shows her as a cat with "mysterious eyes" and earnings. April figures that if she chooses the name Bastet, her symbol could be a cat's head with earnings. She tells the group her idea, and everybody loves it. In fact, her idea inspires Toby's symbol for himself.

If you were to pick the name of Bastet, your symbol could be a cat’s
head with earrings. “Hey,” she said, dropping down to join the group, “I’ve got a great one.”

Everybody liked April’s name and hieroglyph. In fact, Toby said it gave him an idea for a hieroglyph for himself.