File:Enigma rotors and spindle showing contacts rachet and notch.jpg|Two Enigma rotors showing electrical contacts, stepping ratchet (on the left) and notch (on the right-hand rotor opposite '''D'''). | File:Enigma rotors and spindle showing contacts rachet and notch.jpg|Two Enigma rotors showing electrical contacts, stepping ratchet (on the left) and notch (on the right-hand rotor opposite '''D'''). |