man-3
Explanation
The Joke
Two people are walking in a park. One says "What a beautiful pond." The other replies dismissively: "Ech, you can tell it's man-made." The first person, wanting to be inclusive, suggests: "I don't like that exclusive language. Let's say human-made." In the third panel, the second person begins: "But... but you can tell it's... because only a..." and trails off. The final panel reveals why: the pond, seen from above, is shaped like a penis. The second person just says "Ah, nevermind."
The Humor
The comic sets up what appears to be a joke about politically correct language — replacing "man-made" with "human-made" as a gender-neutral alternative. But the punchline swerves entirely: the reason you can tell the pond is "man-made" is not some engineering tell or artificial shoreline — it is because the pond is shaped like a penis, which is the kind of thing a (stereotypically male) human would deliberately do.
The humor works through misdirection. The reader expects the joke to be about the absurdity of inclusive language debates, but instead it becomes a crude visual gag that retroactively makes the original phrasing "man-made" literally accurate in a way the language debate never anticipated. The person who suggested the inclusive language inadvertently makes it impossible to state the obvious: "only a man would make a pond shaped like that." The comic pokes fun at how language policing can occasionally run into situations where the gendered term was, in fact, precisely correct for reasons nobody wanted to articulate.