function trimesh_demo

  face_num = 12;
  node_num = 8;

  face_node = [ ...
    1, 3, 2; ...
    2, 3, 4; ...
    1, 6, 5; ...
    1, 2, 6; ...
    3, 7, 4; ...
    4, 7, 8; ...
    5, 6, 8; ...
    5, 8, 7; ...
    1, 5, 7; ...
    1, 7, 3; ...
    2, 4, 6; ...
    6, 4, 8 ]';
  face_normal = [ ...
    0.0,  0.0, -1.0; ...
    0.0,  0.0, -1.0; ...
    0.0, -1.0,  0.0; ...
    0.0, -1.0,  0.0; ...
    0.0, +1.0,  0.0; ...
    0.0, +1.0,  0.0; ...
    0.0,  0.0, +1.0; ...
    0.0,  0.0, +1.0; ...
   -1.0,  0.0,  0.0; ...
   -1.0,  0.0,  0.0; ...
   +1.0,  0.0,  0.0; ...
   +1.0,  0.0,  0.0 ]';
  node_xyz = [ ...
    0.0, 0.0, 0.0; ...
    1.0, 0.0, 0.0; ...
    0.0, 1.0, 0.0; ...
    1.0, 1.0, 0.0; ...
    0.0, 0.0, 1.0; ...
    1.0, 0.0, 1.0; ...
    0.0, 1.0, 1.0; ...
    1.0, 1.0, 1.0 ]';

  trimesh ( face_node', node_xyz(1,:), node_xyz(2,:), node_xyz(3,:) );

  xlabel ( 'X' )
  ylabel ( 'Y' )
  zlabel ( 'Z' )