The menu form referred to cipher and assumed letters, now transposed into numbers, as 'Switch In' and 'Switch Out.' There are four wheels to mimic the four-rotor Enigma. However, the first three wheels were normally set to zero to begin a run. The last wheel, the bottom rotor on the Bombe, was placed at the position the accompanying link appeared in the message with respect to the previous link. The first switch bank's wheel settings are always 0-0-0-0, regardless of that link's position in the message. The wheel settings for switch bank 2, in this example, are set to 0-0-0-1. Link 6-17 is only one position away from Link 20-0. However, switch bank 4 has a wheel setting of 0-0-0-4 (instead of 0-0-0-3) because Link 14-20 is two positions away from the previous Link 10-7.

The transposed message portion would not appear on the form, but for clarification it is shown here.