So this is a partly completed key I have:
_ R _ _ _ _ T _ _ _ _ _ H _ _ _ _ L _ _ _ P _ _ W
And this is my plaintext/ciphertext:
Plain: INALLCIPHERSYSTEMS Cipher: HORMKRDXIGCTCBELKU
The resultant digraphs:
IN AL LC IP HE RS YS TE MS HO RM KR DX IG CT CB EL KU
I'm tasked with completing the key, but I'm stumped on the second digraph pairing of AL and RM. Given that L and R are in different rows/cols, isn't it impossible to fill in the key s.t. A maps to R? We can't map it to R via shifting to the next row/col entry, and we can't use the rectangle method thing either because if we draw a rectangle from L to R, the opposite adjacent corner that would map to R is directly above L...
Am I missing something? Do you know a possible way of mapping A to R from those two digraphs?