The American animated television series The Simpsons contains a wide range of minor and supporting characters like co-workers, teachers, students, family friends, extended relatives, townspeople, local celebrities, and even animals. The writers intended many of these characters as one-time jokes or for fulfilling needed functions in the town of Springfield, where the series primarily takes place. A number of these characters have gained expanded roles and have subsequently starred in their own episodes. According to the creator of The Simpsons, Matt Groening, the show adopted the concept of a large supporting cast from the Canadian sketch comedy series Second City Television.