Every folktale is the same story.

A story grammar, ninety-seven years old. Propp's insight was that the who and how of a tale vary endlessly, but the what — the functions — are a small fixed set in a fixed sequence. A tsar gives a hero an eagle; a sorcerer gives him a boat; a princess gives him a ring — different surfaces, one function: the donor grants a magical agent. To generate a tale, he wrote, "take any villainy, then a mediation, then a departure… any elements may be dropped, or repeated." That is a generative grammar for plots, and every beat here is chosen exactly that way: the mandatory backbone (a hero is dispatched, departs, resolves the wrong, returns) always appears, while optional functions (interdictions, pursuits, weddings) are rolled in or out, always keeping canonical order. Modern LLM storytellers work differently — they predict words, not functions — but they lean on the same deep truth Propp found: stories that satisfy us share a skeleton, and coherence comes from getting the order of the beats right. Change the seed, keep the grammar, and the tales never run out — because the structure was never the part that varied.