Random House has printed a 50th anniversary edition of Leo Lionni's first book, Little Blue and Little Yellow. In the book, Little Blue and Little Yellow are best friends and love playing together. One day, excited at finding each other, they hug and turn green. After playing for the day, they go home but are unrecognized by their parents. What follows is a lesson on friendship and acceptance.
An excerpt, from Lionni's autobiography, is included in the back of the book. The excerpt explains how Little Blue and Little Yellow came into existence. It's a great example of how necessity is the mother of invention.
Kathryn Otoshi's book One.