Google doodle becomes an enigma in honour of Alan Turing
The Google Doodle was turned into an interactive animated representation of the computing device Turing invented to mark the 100th anniversary of the scientist's birth.
Turing, regarded as the father of computing and artificial intelligence, is best known for his contribution to cracking the German Enigma codes during the second world war with the creation of early computers such as the bombe.
On Saturday scientists and others paying tribute to Turing gathered in Manchester, Oxford and Cambridge to take part in events to celebrate his work.
Plaques in his honour will be erected in Cambridge, Manchester and at his childhood home, Baston Lodge in St Leonards-on-Sea in East Sussex.
A spokeswoman for Alan Turing Year, a campaign to celebrate his work during the whole of 2012, said: "Turing was godfather of computer science and (an) artificial intelligence pioneer, as well as someone who saved literally millions of lives through his code breaking work."
Turing's anniversary comes as a leading academic has claimed that the mathematician may not have committed suicide but had died as a result of an accident.
Professor Jack Copeland, director the Turing Archive for the History of Computing, believes crucial evidence was overlooked following Turing's death from cyanide poisoning at the age of 41 in 1954.
He believes Turing could have died as a result of inhaling the poison he used in amateur experiments rather than deliberately ingesting it.
Professor Copeland, who has written a new biography of the academic to be published shortly, said: "From the records I have been able to obtain, it seems to me very obvious that the inquest was conducted in a very superficial way.
"The coroner didn't really investigate the evidence at all, he just jumped to the conclusion that he committed suicide.
"He seems to have been very biased from the statements in newspapers at the time."
The coroner in Turing's death case ruled he committed suicide "while the balance of his mind was disturbed", adding: "In a man of his type, one never knows what his mental processes are going to do next."
Turing, who was gay, was found guilty of gross indecency with another man in 1952.
To avoid prison, he agreed to receive injections of oestrogen for a year, which were intended to reduce his libido in a process known as "chemical castration".
In 2009 Gordon Brown issued an official apology for the way Turing had been treated.
Professor Copeland, from the University of Canterbury Christchurch in New Zealand, will talk about Turing's death at an event in Oxford on Saturday night.
He said medical evidence suggested Turing died from inhaling cyanide rather than drinking or ingesting it. He said police reported a strong smell of cyanide coming from Turing's lab, where he used it in amateur experiments.
The inquest should be reopened "if possible", he said.
"It would be a terrific thing to do. I think the nation owes it to Turing, in the Second World War he saved the nation."
Perhaps best known for his part in breaking the German Enigma code, Turing was by that time already established as a mathematician of extraordinary capability.
During his time at King's College, Cambridge, he devised the "Turing Machine", a mathematical model that went on to become one of the cornerstones of computer science, when aged just 22.