No edges:
  row-wise order: ( )
  column-wise order: ( )
Directed graph with loops and multiple edges:
  row-wise order: ( 0 1 0 2 1 1 1 3 2 0 2 3 4 3 4 3 )
  column-wise order: ( 0 0 1 1 2 2 4 4 1 2 1 3 0 3 3 3 )
Undirected graph with loops and multiple edges:
  row-wise order: ( 0 1 0 2 1 1 1 3 0 2 2 3 3 4 3 4 )
  column-wise order: ( 0 0 1 1 0 2 3 3 1 2 1 3 2 3 4 4 )
