The number of disjoint interior sub segments is 6
0/1 1/1 -1/-2 -1/-2
0/1 0/1 -1/-2 -1/-2
-1/-2 -1/-2 1/1 0/1
0/1 0/1 1/1 0/1
0/1 1/1 1/1 1/1
-1/-2 -1/-2 1/1 1/1