#Clos network with 12 terminal nodes and 11 switches
28 4

 0 B 16
 1 R 16
 2 R 16
 3 R 16
 4 R 17
 5 R 17
 6 R 17
 7 R 17
 8 R 18
 9 R 18
10 R 18
11 R 18
12 R 19 
13 R 19 
14 R 19 
15 R 19 
16 N 20 21 22 23
17 N 20 21 22 23
18 N 20 21 22 23
19 N 20 21 22 23
20 N 24 25 26 27
21 N 24 25 26 27 
22 N 24 25 26 27
23 N 24 25 26 27
24 N  0  1  2  3
25 N  4  5  6  7
26 N  8  9 10 11 
27 N 12 13 14 15
