In 1936 Turing gave his answer to the question What is a computable number? by constructing his now well-known Turing machines as formalisations of the actions of a human computor. Less well-known is the almost synchronously published result by Emil Leon Post, in which a quasi-identical mechanism was developed for similar purposes. In 1979 these Post toy machines were described in a little booklet, called Posts machine by the Russian mathematician Uspensky. The purpose of this text was to advance abstract concepts as algorithm and programming for school children. In discussing this booklet in relation to the historical text it is based on, the author wants to show how this kind of ideas cannot only help to teach school children some of the basics of computer science, but furthermore contribute to a training in formal thinking.

}, author = {De Mol, Liesbeth} }