Little blue and little yellow

Leo Lionni (May 5, 1910 – October 11, 1999) was an Italian-American writer and illustrator of children's books. Born in the Netherlands, he moved to Italy and lived there before moving to the United States in 1939, where he worked as an art director for several advertising agencies, and then for Fortune magazine. He returned to Italy in 1962 and started writing and illustrating children's books. In 1962, his book Inch by Inch was awarded the Lewis Carroll Shelf Award. [source](