“Turing’s work was so widespread that his influence infused so much of modern thinking. In 1950, for example, he created a test — now known as the Turing Test — that measured the intelligence of a machine.

He is credited with having designed the circuitry for early computers by himself. Turing’s Pilot Ace computer was the one that, in 1954, worked out the cause of a mid-air explosion aboard a Comet jet.

London’s Science Museum is this week opening a year-long exhibition called “Codebreaker: Alan Turing’s Life and Legacy”. It includes a German Engima coding machine on loan from Mick Jagger.

As for Google’s commemorative doodle, I have embedded a video showing how to solve it. Just so that you can be a codebreaker for a day.”