function L = graph_arc_octahedron ( )

%*****************************************************************************80
%
%% graph_arc_octahedron() sets up the octahedron arc list.
%
%  Discussion:
%
%    The graph has 8 nodes.
%    The graph has 12 edges or 24 arcs.
%
%      1---2
%     /|   |\
%    8-+---+-3
%    | |   | |
%    7-+---+-4
%     \|   |/
%      6---5
%
%  Licensing:
%
%    This code is distributed under the MIT license. 
%
%  Modified:
%
%    30 April 2026
%
%  Author:
%
%    John Burkardt
%
%  Output:
%
%    integer L(arc_num,2): the arc list.
%
  L = [ ...
    1, 2; ...
    1, 6; ...
    1, 8; ...
    2, 1; ...
    2, 3; ...
    2, 5; ...
    3, 2; ...
    3, 4; ...
    3, 8; ...
    4, 3; ...
    4, 5; ...
    4, 7; ...
    5, 2; ...
    5, 4; ...
    5, 6; ...
    6, 1; ...
    6, 5; ...
    6, 7; ...
    7, 4; ...
    7, 6; ...
    7, 8; ...
    8, 1; ...
    8, 3; ...
    8, 7 ];

  return
end
