Five-line XKCD ekphrasis
I can't quite make up my mind about this one - I have a kind of instinctive aversion to the "same word in first and last lines" ones; on the other hand, it is very elegant - I like the way it shifts between "noughts and crosses" and "tic-tac-toe", and the use of Munroe's name.Anyway, a non-repetitive rewrite:There's a game and it's called tic-tac-toe.It may give you some pleasure to knowYou can outcomes displayIn a fractally waySo you know where your marker should go.I think I would prefer a rewrite that was just your limerick but with a different last line, though. Let me mediate for a while on things that rhyme with "crosses" and perhaps I shall return to this comic.
I agree that repeating the rhyme from the first line isn't to everyone's taste, but it was very common among the earliest limericks. I like to do it occasionally as a nod to the limerick's roots - used sparingly, I think it gives the poems a nice, old-fashioned flavour.
I think there are a couple of original Lears where the first and last lines are exactly the same!