 So how to construct a universal machine U out of the set of basic operations we have at our disposal? Turing’s approach is the construction of a machine U which is able to (1) ‘understand’ the program of any other machine \(T_{n}\) and, based on that “understanding”, (2) ‘mimic’ the behavior of \(T_{n}\). To this end, a method is needed which allows to treat the program and the behavior of \(T_n\) interchangeably since both aspects are manipulated on the same tape and by the same machine. This is achieved by Turing in two basic steps: the development of (1) a notational method (2) a set of elementary functions which treats that notation—independent of whether it is formalizing the program or the behavior of \(T_n\)—as text to be compared, copied down, erased, etc. In other words, Turing develops a technique that allows to treat program and behavior on the same level.