bayw reversed = wyab → w→p (w-7), y→a (y-24? no). Not clean.
The phrase "danlwd wy py an bayw bayw" — the word "paper" at the end suggests the cipher might be shifting letters.
But if you just need the plaintext and the cipher is ROT13? ROT13(danlwd) = qnayjq — nonsense. So not ROT13.