Instead of a reflector, they could have used 27 contacts, and either had a 27th lightbulb to indicate the output was the same as the input, or made each key a d

Instead of a reflector, they could have used 27 contacts, and either had a 27th lightbulb to indicate the output was the same as the input, or made each key a dual-throw dual-post switch so that the 27th output would get wired to light up the switch corresponding to the input key. That would remove the weakness that no letter is ever enciphered as itself. Edit: never mind: you'd actually need 28 contacts, since the reflector can only reflect an even number of contacts. With an even number of unused contacts on the input side of the rotor stack, you could connect them together in pairs to get extra passes through the rotor stacks. If they added / (for use as a number shift symbol, so 1123 would be /AABC/ ) to their alphabet, then they could use 28 contacts and have something like described above. However, without modifying the alphabet space to have an odd number of symbols, all other workarounds I can think of require an odd number of used inputs at the one end of the rotor stack and and even number of contacts at the reflector end. The Germans used Q or Z as their number shift symbol when enciphering digits for Enigma traffic, correct?