Turing suggested that, as a first step, he write a program that would enable the Ferranti Mark I to simulate itself....The trace program Strachey wrote included

Turing suggested that, as a first step, he write a program that would enable the Ferranti Mark I to simulate itself....The trace program Strachey wrote included over a thousand instructions—at the time it was the longest program that had ever been written for the Ferranti Mark I. Strachey had it up and running after pulling an all-nighter, and when the program terminated, it played “God Save the King” How many 'computer programmers' could do this in today's world?