Turing centenary : exhibitions and petitions

As a mathematician and a Mancunian, I am honour-bound to think that Alan Turing is great.  But when I visited Alan Turing and Life’s Enigma at Manchester Museum, what most impressed me about the man was not that he developed the encoding scheme for one of the first programmable computers, it was that as soon as he had access to it he was doing some really clever mathematical modelling, looking for a link between reaction-diffusion equations and morphogenesis.  As someone who does mathematical modelling, with computers, for a living, I was amazed to see the birth of my profession displayed in printouts with notes scribbled on them.  The exhibition also showed Turing’s papers on the subject and the cards he got from academics around the world, requesting that he send them a copy.  I didn’t realise that’s what people did at the time.  I guess that was the best way before Turing’s ideas about machines that compute slowly revolutionised the world.
The exhibition is part of the celebrations of the centenary of Turing’s birth.  This year also sees two petitions to get him remembered, one on the ten pound note and the other on the fourth plinth of Trafalgar Square.
The fourth plinth idea sounds brilliant.  By putting Turing in the square with Nelson, the nation can show its gratitude for a very different type of war hero.  But the brilliant idea looks doomed to failure.  In the 1990s a commission convened by the RSA recommended that the plinth be used for the temporary display of artworks.  However, there may be a way to do something.  In 2008 Terry Smith sought to get a permanent statue of Air Chief Marshal Sir Keith Park erected on the plinth.  This did not happen but a temporary statue was erected on the plinth in Autumn 2009 (although some people didn’t appreciate it).  Perhaps a temporary statue is all we can hope for on this occasion too, but that is worth signing the petition for.
Turing on the tenner looks a lot more hopeful.  The current Bank of England £10 note is in series E, whereas the £20 and £50 notes are in series F.  The Bank must consider a series-F tenner at some point so getting Turing on there makes sense.  But what to depict?  Behind the current image of Darwin is a depiction of the voyage of the Beagle.  While I would love morphogenesis to appear on the tenner I know what everyone will say: It must depict the cracking of the Enigma.  This may be inevitable but I have a further suggestion.  The Adam Smith £20 note shows a seemingly innocuous observation on the manufacture of pins but this telling detail can be extrapolated to explain the Wealth of Nations.  Similarly, one idea of Turing's can be extrapolated to explain many of his others, and so many aspects of the modern world, from computers to the Allied victory in World War II.  The £10 note should depict the Turing Machine!