Hello, red fox, said the little frog. Welcome to my birthday party! But that's not a red fox, said Mama Frog. That's a green fox. Suddenly, Mama Frog also sees a red fox. Because if you look long enough at the green fox and then at the black dot on the opposite white side, the fox appears there - as if by magic - in red color. In Eric Carle's new picture book, children discover the fascinating interplay of complementary colors with their own eyes. Thus, the blue cat becomes orange, the yellow butterfly turns purple, and the red snake becomes green. This wonderful interpretation of Goethe's color theory is a feast for the eyes, not only at first glance but also at second glance.