Nick Dow's story of the Gypsy Wagon inevitably reminds me of the story of what Wikipedia calls the Ship of Theseus, but which I know as a story above axes (as retold by Terry Pratchett, among others).

The King of the Dwarves had as his symbol of authority an axe. After years of use, the handle wore out and was replaced. Later, the blade wore out and was replaced. Then the handle wore out again and was replaced. And then the blade was replaced. And so on. But it was still the Dwarf King's Axe. Because it was.

As long as there is continuous variation, something is, at least arguably, the same, even if the beginning and ending states are completely different. A lesson for students of folklore.

Wikipedia version: https://en.wikipedia.org/wiki/Ship_of_Theseus.

Wikipedia traces it to Plutarch, who is responsible indirectly for a lot of folklore, because he inspired so many Shakespearean distortions. :-)