When was that XKCD published (https://xkcd.com/1425/) ? Yeah, I remember seeing for the first time, I don't remember my reaction then. But now when I see it, I am stumped!
To know the date of publication of a given xkcd comic, go to https://xkcd.com/archive/, search for the title you're after, then the date of publication is displayed in the mouse-over text.
