Triangular diagram classifying communities at the second level by their relationship with the walnut structure.

Each community is depicted by a circle located at point (x, y) inside the equilateral triangle, which corresponds to the composition (x1, x2, and x3) of firms belonging to the IN, OUT, and GSCC components that are represented in three-dimensional space; the one-to-one correspondence between (x, y) and (x1, x2, x3) is illustrated in the associated figure (a). The size of the communities is reflected by the area of their associated circles. The triangular region is decomposed into six domains with the average composition (, , ) of the IN, OUT, and GSCC components for all firms, as designated in the associated figure (b); see the text for more detailed information on the domain decomposition.