n=4 k=2 b=2 connected=True: 18 labelled systems, 4 iso classes
--- class 0
   {0123}:0123
   {012}:01|2  {013}:01|3  {023}:0|23  {123}:1|23
   {01}:01  {02}:0|2  {12}:1|2  {03}:0|3  {13}:1|3  {23}:23
--- class 1
   {0123}:0123
   {012}:01|2  {013}:01|3  {023}:0|23  {123}:1|23
   {01}:01  {02}:0|2  {12}:1|2  {03}:0|3  {13}:1|3  {23}:2|3
--- class 2
   {0123}:0123
   {012}:0|12  {013}:03|1  {023}:03|2  {123}:12|3
   {01}:0|1  {02}:0|2  {12}:1|2  {03}:0|3  {13}:1|3  {23}:2|3
--- class 3
   {0123}:0123
   {012}:0|12  {013}:01|3  {023}:03|2  {123}:1|23
   {01}:0|1  {02}:0|2  {12}:1|2  {03}:0|3  {13}:1|3  {23}:2|3
