He did not entirely invent the Colossus computer. Bletchley Park had already produced a counting machine dubbed "Heath Robinson" (British equivalent of the American "Rube Goldberg Machine"), but it was highly unreliable due to the need to synchronize two paper tapes at high speeds. The key improvement to the existing "Heath Robinson" design that Tommy Flowers made was to replace the "encryption key" tape with high speed electronics that could be programmed to generate the key in real time as the "encrypted message" tape was being read. That completely eliminated the problems with synchronizing of paper tapes. But the logical principals used to break the cipher were identical in both the "Heath Robinson" and the Colossus.Once initial problems with the prototype Colossus Mark I had been resolved and it was reliably working on messages at 5000 characters per second Tommy Flowers added a five level deep pipeline, providing parallel processing in the finished Colossus Mark II permitting it to work on messages at 25000 characters per second.