writers was "Marge in Chains", an existing idea that they were assigned. The first draft of the script was based on research about women in prison conducted by Oakley and Weinstein, making it "slightly more realistic" than the final version of the episode, in which many realistic elements were replaced. After season four, most of the original staff left the show. Before David Mirkin arrived to take over as showrunner for season five, Oakley, Weinstein, O'Brien and Dan McGrath were the only writers working on the show and spent a month mapping out most of the season's episodes. Oakley and Weinstein wrote several episodes for season five, penning the "Terror at 5½ Feet" segment of "Treehouse of Horror IV", "$pringfield (Or, How I Learned to Stop Worrying and Love Legalized Gambling)", "Lisa vs. Malibu Stacy", the show's 100th episode "Sweet Seymour Skinner's Baadasssss Song" and "Lady Bouvier's Lover". For season six they wrote "Sideshow Bob Roberts", basing much of the episode on the Watergate scandal, in which they had a great interest. They also wrote "Grampa vs. Sexual Inadequacy", and "Bart vs. Australia". The writing staff wanted to do an episode in which the Simpsons family traveled to a foreign country; they selected Australia because they thought that everyone in Australia had a good sense of humor and "would get the jokes", with the episode being intentionally inaccurate. The episode proved somewhat controversial; some Australian fans said the episode was a mockery of their country. Shortly after it had aired, the Simpsons staff received over a hundred letters from Australians who were insulted by the episode. The pair wrote the two-part episode "Who Shot Mr. Burns?", which was initially proposed by series creator Matt Groening. While deciding who the culprit was, Oakley and Weinstein pitched Barney Gumble because he was a character that could go to jail and it could change the dynamic of the show. Mirkin suggested Maggie because he felt it was funnier and wanted the culprit to be a family member. Oakley and Weinstein were initially unsure about having Maggie as the culprit, and it was decided that the episode would end with Maggie shifting her eyes and making it look like it was not a complete accident. As showrunner Oakley and Weinstein were appointed executive producers and showrunners of the seventh and eighth seasons. They were chosen partly because they had been with the show since