Independent, or private, schools have flexibility in staff selection and educational approach. Many are Montessori and Waldorf schools (the latter also known as Steiner schools, after their founder Rudolf Steiner). Other independent schools include democratic or free schools, such as Clonlara School, which is the oldest, continually operating K-12 alternative school in the country, the Sudbury schools, open classroom schools, those based on experiential education and schools using an international curriculum such as the International Baccalaureate and Round Square schools.