In the history of cryptography, the NEMA was a ten wheel rotor machine 
designed by the Swiss Army during World War two as a replacement for their Enigma machines.
NEMA uses ten wheels, of which four are normal electrical rotors with twenty six contacts 
at each end that are scramble wired in a way unique to each rotor type. 
One is an electrical reflector with one set of twenty six pairwise cross connected contacts
and the remaining five are drive wheels, with mechanical cams that control the stepping 
of the rotors and the reflector. The wheels are assembled on an axle in pairs consisting 
of a drive wheel and an electrical rotor.