In this swamp you do not sign your name. You sign your tongue. Every amphibian in the pond carries a print at the tip of it as individual as a claw-mark — pressed wet into the ledger, unfakeable in living memory, admissible in any court that hops. Exhibit A is two of those prints, lifted on the same night, under the same glass, by the same steady flycatcher, and mounted on one card so the jury never has to hold them apart. They are nearly identical. They belong to two frogs with one face. Nearly identical is the entire problem, and also the entire solution.
The hook is on the right print. The right print is not PeePoo's. It never was.
Read the left print first. That is PeePoo's. It lies down flat and finishes clean, the way an honest plank finishes — no flourish, no afterthought, nothing hidden in the follow-through. A frog who has never once needed a signature to lie leaves a print exactly like this. It is, forensically speaking, boring. Boring is the highest compliment a tongue-print can earn. Boring does not forge checks.
Now the right print. Same width, same honest-looking body — and then, at the very tip, where a tired forger relaxes and the truth leaks out, a small hook. A curl. A tail on the letter that should not be there. You would not notice it unless you were the sort of frog who studies the difference for a living, and one such frog did, twice, and then a third time to be sure her own eyes weren't the ones lying. The hook is on the right print. The right print is not PeePoo's. It never was.
What Exhibit A proves is narrow and total at once. It does not prove who signed the seventeen checks — that is Exhibit B's job, and the checks all carry the flat print, the copied plank, because a good forger copies the honest tongue and not his own. What Exhibit A proves is that there are two tongues in this case wearing one face, that they can be told apart by a hook the guilty one cannot un-curl, and that the frog in the dock is the one whose print has no hook to hide. Same clutch. Same pond. Same face. Different tongue. The court has had the second frog the whole time and kept staring at the first.