Doonesbury by Garry Trudeau for July 08, 1975
Phred: Class, once again I'd like to welcome all of you to the Vietnam People's re-education center! As you know, gang, indoctrination is the name of the game here! We're here to learn about communism! Now, judging from yesterday, it is clear that many of you find the material a little dry. I can understand this, but in the future, I'm afraid I must insist on your undivided attention! Any more water fights, and heads are gonna roll!