There once was a man from St. Paul
Who fell in the spring in the fall.
'Twould have been a sad thing
If he fell in the spring,
But he didn't; he fell in the fall.
This limerick, though it sounds at first to be cute nonsense, has one remarkable characteristic -- it is constructed around a pair of triple synonyms, and it is coherent regardless of which definition you choose in each of the two synonyms' two appearances.
The key words are 'spring' and 'fall'. Each of these has three meanings:
- A physical action (springing into the air and falling back to the ground).
- A season of the year (spring, summer, winter, fall).
- A body of water (spring as a small river, and a waterfall).
For clarity, I am going to refer to each of these three sets as a "meaning set".
There is no requirement that the listener or reader select the same meaning the two times each of these words appears. The only constraints are that in the first appearance ("fell in the spring in the fall"), 'spring' and 'fall' come from different meaning sets, and that in the second appearance ("been a sad thing if he fell in the spring," etc.) the two come from the same meaning set. Finally, since the second occurrence specifies that the man from St. Paul did not fall in the spring, we have to subtract from the second occurrence whichever sense of spring the reader selected in the first occurrence, lest we have a contradiction.
Therefore there are six permutations for the first occurrence, and two for the second. The occurrences are independent, so there are a total of twelve possible interpretations to the limerick.
I learned the poem in third grade and was fascinated by it. It still delights me and I look forward to teaching it to my nieces and nephews when they get old enough to understand.