Video explanation
A keypress sends a signal through the plugboard, three rotors and reflector back to a lamp, alongside stepping and exploded components.
Layered substitution
The plugboard and rotors map letters, with a reflector returning the signal along another path.
Stepping changes mappings
Keypresses change rotor state, allowing the same letter to produce different results at different positions.
Settings as key material
Rotor order, positions, ring settings and plugboard connections jointly define the transformation; recovery needs matching settings.