1425	 Flow Diagrams Turing Machines And Languages With Only Two Formation Rules	 In the first part of the paper flow diagrams are introduced to represent inter al. mappings of a set into itself. Although not every diagram is decomposable into a finite number of given base diagrams this becomes true at a semantical level due to a suitable extension of the given set and of the basic mappings defined in it. Two normalization methods of flow diagrams are given. The first has three base diagrams the second only two. In the second part of the paper the second method is applied to the theory of Turing machines. With every Turing machine provided with a two-way half-tape there is associated a similar machine doing essentially the same job but working on a tape obtained from the first one by interspersing alternate blank squares. The new machine belongs to the family elsewhere introduced generated by composition and iteration from the two machines L and R. That family is a proper subfamily of the whole family of Turing machines.
