I've always strongly felt that you can make a "Buffalo buffalo...." sentence with any number of buffalos, and without resorting to the city of Buffalo at all (which I think is cheating).
Without resorting to the city of Buffalo, it becomes much more obvious that the sentence can go on for ever. At each iteration you simply take the object of the previous sentence and make it the subject of the next sentence, and say that those buffalo also bully.
So, first we substitute the word "cows" for the noun "buffalo" and the word "bully" for the verb "buffalo," and then we mark each equivalent noun and noun-phrase (to make the substitutions clear), and we get
- Bully! -- the imperative
- Cows bully.
- Cows bully cows1
- [Cows that cows bully]1 bully -- i.e. the cows that were being bullied in #3 themselves also bully
- [Cows that cows bully]1 bully cows2
- [Cows that [cows that cows bully]1 bully]2 bully -- i.e. the cows that were being bullied in #5 themselves also bully
- [Cows that [cows that cows bully]1 bully]2 bully cows3
The recursive nature becomes much more obvious. Each time a sentence ends with the verb ("bully" i.e. saying that some cows bully), we can ask "well, who do they bully?" And each time we answer that by specifying that they bully cows, we can take those cows (the object of the previous sentence) and say that they themselves (now as the subject) also bully.
Once we realize that (1) any object in a valid sentence, e.g. "cats" in the sentence "dogs bite cats," can be turned into a noun-phrase with an optional "that", e.g. "cats (that) dog bite," and that (2) any animate noun-phrase can be followed by a transitive verb, e.g. "cats dogs bite eat," and finally that (3) transitive verb can take an object, e.g. "cats dogs bite eat mice," we can then prove from those three axioms that we can continue the cycle indefinitely: "mice (that) cats dogs bite eat steal crumbs." And then we don't need to confuse matters with the city of Buffalo.