The Turing machine, hypothesised by Alan Turing, was originally led by the question, ‘Can complex thinking be mechanised?’  It is an abstract machine that manipulates symbols (consisting of zeros and ones), according to a set of rules (code).  A Turing machine can be  thought of as an infinite piece of tape (which acts like the memory in a typical computer). It essentially has a read/write head that goes over the top of the mark on the tape. Despite its simplicity, the machine can simulate any computer algorithm, no matter how complicated it is. For more information visit the University of Cambridge website.