Not sure this really belongs here, but I did not know where else to post it.

How difficult would it be to create a formula that allows one to create a private and public key using just paper and a pencil?

To me this would be the most secure possible method for making a wallet, as the private key will never have existed on a computer, even one thats offline.

Of course one would also need a hardware random number generator, but that can be easily done.  (Using dice, a falling pen, ect.)

I know the math has to be pretty extreme, so its just a thought.