Tinker with a virtual Colossus, the world's first programmable electronic digital computer

I wasn't expecting the Virtual Colossus to be implemented in three-dimensional space as a browser-based first-person experience. It's a little nightmarish, even, clacking rhythmically, insistently, ominously. And you need to help Britain defeat the Nazis! Decrypt a Lorenz S742 message!

This document will take you through an example process used on Colossus to get the start positions of a received message. There wasn't a set program which would run to work out the settings, it was a matter of following a "menu" of different algorithms and sometimes required knowledge of what worked on a particular radio link.

Colossus was not able to run a sequence of algorithms or use the results of previous calculations (like we would expect from a computer today), each run required a decision by the operator or code breaker assigned to that machine on which operation would be the next best to run.

I don't even want to touch any of its knobs, dials or other protuberances, lest I lose the war. There's even a clock on the wall to remind you that you're not helping.