Blue hat, green hat

Sandra Keith Boynton (born April 3, 1953) is an American humorist, songwriter, director, music producer, children's author, and illustrator. Boynton has written and illustrated over eighty-five books for children and seven general audience books, as well as over four thousand greeting cards, and seven music albums. She has also designed calendars, wallpaper, bedding, stationery, paper goods, clothing, jewelry, and plush toys for various companies.