man-3
Explanation
This comic plays on the modern push for gender-neutral language, specifically the replacement of "man-made" with "human-made."
Two people are walking in a park. One admires a pond: "What a beautiful pond." The other responds dismissively: "Ech, you can tell it's man-made." The first person corrects the language: "I don't like that exclusive language. Let's say human-made."
In the third panel, the second person starts to explain how you can tell it is artificial: "But... but you can tell it's... because only a..." He trails off, unable to finish the sentence. The final panel reveals why: the pond, when viewed from a wider aerial perspective, is shaped exactly like a penis.
The joke is that the original speaker was about to say "you can tell it's man-made because only a man would make a pond shaped like that." The language correction from "man-made" to "human-made" inadvertently removed the very word that was essential to the observation. The pond's phallic shape is something stereotypically associated with male humor and behavior -- the kind of juvenile thing "a man" (specifically) would do, not just any human. By insisting on the gender-neutral term, the first speaker accidentally defused the precise gendered point the second speaker was trying to make.
The comic is a gentle satire of the sometimes awkward tension between inclusive language reform and situations where gendered language carries specific, relevant meaning. The bald man's defeated "Ah, nevermind" captures the moment of realizing that the politically correct phrasing has made his joke unexplainable.