Teaching coding to kids is a trend that is on the rise. A number of children’s books are using fictional storylines to teach the fundamentals of coding - Girls Who Code is releasing two books, a fiction novel called "The Friendship Code," and an illustrated coding manual, and Gene Luen Yang’s best-selling graphic novel series “Secret Coders” follows a group of kids who discover that their school’s janitor has a secret underground coding school. There are also a number of organizations that have developed apps and online lessons to teach kids coding as well. Code.org provides free online coding lessons, and has crafted coding curriculums for elementary, middle and high school students. Scratch Jr, a coding program designed for 4- to 7-year-olds, now has some five million users, and last year, Apple released a free app to teach the programming language Swift.