These values are represented by a set of 11 concentric circles, of radii 0 up
to 10, intersected by lines emanating from the inner circle and connecting the
characteristics. With respect to the axis y = 0 (i.e. the horizontal axis) these
lines have angles that can be chosen, in principle arbitrarily, but a reasonable
choice is to consider them disposed approximately parallel to the lines y = 0,
y = x and y = −x (i.e. the horizontal axis and the two lines at 45 degrees to the
horizontal one). In Figure 2 we present this diagram, which is not the original
one (as found in [1]), but it gives quite well the idea of what Italian sommeliers
should handle when performing food and wine matching. Some characteristics
of the food match the wine by opposition while others by accordance. To be
more precise, if we associate a set of Cartesian coordinates (x, y), the diagram
has essentially three main symmetries: one bottom-up that corresponds to the
horizontal line y = 0 describing a matching by accordance, the other two,
describing a matching by opposition, correspond to the bisection lines y = x
and y = −x.