In running, pacing is the act of moving at a specific speed. This is extremly useful when you are going long distances, as you don’t want to tire yourself out too soon. Want to run 5 miles in 1 hour? If you can run 1 mile in 12 minutes and keep at that steady pace, you’ll be just fine.
In writing, pacing is similar to the passage of time. You encounter it every day but probably don’t realize it. Every story has a beginning, middle, and end. How this story advances is pacing. Have you ever read a book (or seen a movie for that matter) and went “The beginning and end were great, but the middle was a bit slow.” ? That’s poor pacing.
Pacing is extremly important when it comes to writing humor. You have the setup, the delivery, and then the punchline. The start of the joke and the end of the joke should be close together in order to keep the audience’s interest*. In a cartoon, panels mark the passage of time, ie: Panel 1 has the setup, panel 2 has the delivery, and panel 3 has the punchline. There’s no need for a panel 4 as that would be extra, wasted time that would actually take away from the joke.
And that’s why this joke is actually very funny.
At least…I thought it was very funny
** An excellent reference on writing comedy is Mel Helitzers ‘Comedy Writing Secrets‘. I highly recommend this…I refer to it a lot as I write this strip.