Lorenz SZ42
The SZ40/42 added a key to each five-impulse teleprinter character: five χ wheels that move every character, five ψ wheels that move together when two motor wheels allow, and on the SZ42 a limitation from χ2 (and ψ1, or the plaintext) one or two characters back. Bletchley called it Tunny; Colossus was built to set its χ wheels. Tested against a real SZ42’s 2007 transmissions.