function L = digraph_arc_cycler ( )

%*****************************************************************************80
%
%% digraph_arc_cycler() returns the arc list for a 9-node example.
%
%  Diagram:
%  
%           A
%           V
%    9--><--7---<--3--><---4
%    |            /|      /
%    V           A |     /
%    |          /  |    /
%    5----<----1   V   A
%    |        /    |  /
%    V       A     | /
%    |      /      |/
%    2-->---8---<--6
%     \------>----/
%
%  Licensing:
%
%    This code is distributed under the MIT license.
%
%  Modified:
%
%    25 April 2026
%
%  Author:
%
%    John Burkardt
%
%  Output:
%
%    integer L(16,2), the arc list.
%
  arc_num = 16;

  L = [ ...
    1, 3; ...
    1, 5; ...
    2, 6; ...
    2, 8; ...
    3, 4; ...
    3, 6; ...
    3, 7; ...
    4, 3; ...
    5, 2; ...
    6, 5; ...
    6, 8; ...
    7, 7; ...
    7, 9; ...
    8, 1; ...
    9, 5; ...
    9, 7 ];

  return
end
