This  file  uses
1/1/1  2/2/2  3/3/3
3/3/3  2/2/2  4/4/4
3/3/5  4/4/6  5/5/7
5/5/7  4/4/6  6/6/8
5/5/9  6/6/10  7/7/11
7/7/11  6/6/10  8/8/12
7/7/13  8/8/14  1/9/15
1/9/15  8/8/14  2/10/16
2/2/17  8/11/18  4/4/19
4/4/19  8/11/18  6/12/20
7/13/21  1/1/22  5/14/23
5/14/23  1/1/22  3/3/24
