Back in his Channel 101 days, Dan Harmon learned of the wisdom of Joseph Campbell and would preach the building blocks of storytelling constantly. This eventually led to his famous story wheel, which he uses to break down every story on his shows Community and Rick & Morty. In explaining the importance, indeed ubiquity, of story structure, Harmon cited an interesting-sounding instructional video from the Seventies:
 

[Rob] Schrab has this video we watch all the time: It’s an orientation video designed to teach mentally retarded girls about their period. The protagonist is a retarded girl. She starts asking questions about periods. She’s led into a bathroom by her older sister, and after a very uncomfortable road of trials, things take a turn for the bizarre. I won’t go into detail. Not only is the protagonist going on a journey, the audience is, too.

 
I’ve tracked down the movie, and it’s a beaut. It’s about ten-minutes long, and doesn’t have credits but must have as a title “All Women Have Periods.” In it a little girl with Down syndrome named Jill asks her mother, father, and older sister Suzy about what a period is and receives a full-blown tutorial in the bathroom from her sister.
 

 
The following must be one of the greatest dialogue exchanges in movie history:
 

“Suzy? What’s a sanitary pad?”
“Come on, Jill, I’ll show you. I’m having my period now.”

 
I’ll say this: It’s a testament to the power of repetition—everything in the movie is explained four times. The next time someone asks me what a period is, I’m going to say, “Blood from inside a woman’s body comes outside from an opening between her legs. All women have periods about every four weeks for three or four days…..” I hope no one asks me.