The Yellow Brick Line is a metro line built on what was once the Yellow Brick Road, one of Emerald City's oldest and most storied roads.
West and Ojo's school is named after Oscar Zoroaster Phadrig Isaac Norman Henkel Emmannuel Ambrose Diggs, one of the most powerful and celebrated Wizards of Oz.
Ojo is inspired by a character in Baum's books: a munchkin boy named Ojo the Unlucky, who first appeared in The Patchwork Girl of Oz.
Patchwork Doll is inspired by the Patchwork Girl, a character from Baum's books who is a living doll made of various scraps.
A sign can be seen for Nome King Cave Tours. The Nomes live inside mountains, where they mine the magical metals and jewel stones that lie buried in rock and ore.