[T.B. Yoits]

The Brits, with critical help from the Poles and an unidentified inventor who built them a copy of the three rotor machine, could decipher the three rotor code but knew they couldn't break the four rotor code.

American Joe Desch and a team hidden in the National Cash Register building in Dayton Ohio along with a team in the U.S. Naval Computing Machine Laboratory built electro-mechanical computers to decipher transmissions from the four rotor Enigma machines.

https://prc68.com/I/NCR.shtml

[SunkenCiv]

Thanks! The Germans added a rotor and ‘blinded’ the codebreakers for some months before a fix was figured out. Didn’t know the NCR people had that role.

https://en.wikipedia.org/wiki/Bombe

https://en.wikipedia.org/wiki/Colossus_computer

[linMcHlp]

NCR DAY