It may be true that there are a limited number of gags out there floating around this universe of ours. How often do you open the comics pages of the newspaper (if you actually look at a print copy of the newspaper) and see similar jokes in some of the strips? Now, these two strips are separated by more than a dozen years, but they rely on the same joke.
Then here's this one from Fox Trot that ran back in 2005. It's the same idea, just executed a little differently:I thought it was kind of cool, anyway.
BTW, mine was first. : )