Figure 13  a) There are three distinguishable clusters: {1, 2, 3}, {4, 5, 6}, {7, 8, 9} but as long as c is below 4/11 there is only one maximal clique embracing all intervals. Not until c is larger than 3/5, the wanted three sets will emerge as maximal cliques. b) Here, the situation is different. Intuitively, only one set embracing all intervals should emerge. But this homogenous set will be split into two maximal cliques when c is greater than 3/5: one contains interval 5 and one interval 6.