“How can you write a complete story without a conventional plot? We often hear that in short stories, the main character must change. But in some stories, including some by Grace Paley, the characters don’t change. Instead, her stories change the reader. You’re different by the time you reach the end.” We’ve told you about The Atlantic’s “By Heart” series plenty of times before. This week, it’s Alice Mattison, who touches on everything from character development to the strange stories of Grace Paley.