By repeating these experiments, some shapes, when dissolved, seem to come back; little by little categories tend to clearly stand out, in numbers, recurrences appear. Sometimes certain "melts" do
not seem to belong to any family. Once again, the numbers will perhaps define new categories.
The recordings on tapes tend to constitute an exhaustive catalogue of various groups until now identified, and it is easy to understand that their quantity is a function of the degree of accuracy used to define them.