For the first four seasons, Sorkin wrote almost every episode of the series, occasionally reusing plot elements, episode titles, character names, and actors from his previous work, "Sports Night", a sitcom in which he began to develop his signature dialogue style of rhythmic, snappy, and intellectual banter. Fellow executive producer and director Thomas Schlamme championed the "walk and talk," a continuous shot tracking in front of the characters as they walk from one place to another that became part of "The West Wing"<nowiki>'</nowiki>s signature visual style. Sorkin's hectic writing schedule often led to cost overruns and schedule slips, and he opted to leave the show after the fourth season, following increasing personal problems, including an arrest for possession of illegal drugs. Thomas Schlamme also left the show after the fourth season. John Wells, the remaining executive producer, took the helm after their departure.