Reply To: Challenge 10B
@Chinchinchilla
If you already have the completed grids, in terms of programming – you could split the ciphertext into digraphs, look up each digraph’s position in its grid (you can define the two square grids as lists), recombine the row and column values according to the four square rule and read off the plaintext letters from the other grids. A small loop or function that converts one digraph at a time is all you need really.