"Not quite sure about what you just spoke,
was that a parable, or a very subtle joke?"

Not sure myself.

The plain text explanation (I don't do this very often so, if you wish to make sense of my posts in the future pay attention, if you don't then you're probably not reading this anyway):

The Latin preposition de, from, takes the ablative, the concept behind of requires the genitive (yes I spelled it wrong before). The Latin for dam is claustrum, -i which is 2nd declension, neuter; the genitive would be claustri and the ablative would be claustro. How you would tell which it was from looking at the dam is beyond me; therefore we must take this in some other sense.

To wit; the secret meaning:

This is probably something that will vary depending on the dialect being spoken. Some of these are the kinds of things that get huffy prescriptionists to proclaim loudly that their version is obviously superior to (or is it superior than?) any other version because their version "makes sense". In truth, ninety nine times out of ten (n)either version makes sense and it is just a matter of what the individual learned in the formative years.

Side note: A good way to decide which is correct in such matters is to flip a coin. Decide before you flip what each side means, e.g., Heads = from and Tails = of. Flip the coin and look at the result. You will then either say, "Aha! I was right all along!" or "No, no! That can't be right!" Then go with what your heart told you all along but which you didn't know until you actually flipped the coin. When you get good at this technique you will no longer need the coin.

Further side note:

There is a support group available if you start understanding me and it doesn't bother you that you understand me. There is one out there who would fit this group but doesn't feel the need for the support group. Hi Elf