In addition to Cohen, Futurama is staffed by a roster of Ivy League graduates with backgrounds in science and math. But while writing one episode, the staff had created a plot so complex that the crew soon found itself stumped. The episode was The Prisoner of Brenda from the sixth season, and it involved a brain switching machine that could swap the minds of any two people that stepped into it. There was only one problem once used, the machine couldnt be used twice to swap the same two minds back to normal. This means numerous pairs of other characters would have to use the machine in a roundabout plan to restore everyones mind to their proper body. Though the idea sounded like a winner to the writers, Cohen recalled that they soon realized they had to create a mathematical explanation that could get everyones mind back. It was like a nightmarish SAT problem for the staff.