Secret Code

Once I had a secret code,
Where A was B, and B was G.
G was K, and K was J;
And J was M, and M was P.
V was X, and X was V,
And U was I, and I was U.
87 stood for Z,
And 2 for T, and T for 2.
O was 12, and Q was 17;
I still don’t know what those numbers mean.
That is how we won the war;
My secret code’s no secret anymore.
H was 9, and S was 33;
Oh, how that confused the enemy!
Then a recent survey showed
That I don’t understand my secret code.