Elephant and Piggy through the years
Infant era: Big hit, compelling pictures.
Toddler era: Funny stories, still going strong.
Preschool era: Could not compete with graphic novels, licensed franchises, books with basic sci-fi and adventure tropes. They still have an occasional appeal.
Kindergarten era: They’re back! Readable without adult help. He’s read eight of them in the past day.
Mo Willems designed these perfectly on several levels, sort of creating multi-dimensional objects, in a sense.