#nexus
[This file provided by Paul Lewis, from the NCL test suite. ]

begin taxa;
  dimensions ntax=8;
  taxlabels taxon_1 taxon_2 taxon_3 taxon_4 taxon_5 taxon_6 taxon_7 taxon_8;
end;

[!
********************************************
* Interleaved, lower-triangular, diagonals *
********************************************
]
begin distances;
  format interleave;
  matrix
    taxon_1   0
    taxon_2   1  0
    taxon_3   2  3
    taxon_4   4  5
    taxon_5   7  8
    taxon_6  11 12
    taxon_7  16 17
    taxon_8  22 23

    taxon_3   0
    taxon_4   6  0
    taxon_5   9 10  0
    taxon_6  13 14 15
    taxon_7  18 19 20
    taxon_8  24 25 26

    taxon_6   0
    taxon_7  21  0
    taxon_8  27 28  0;
end;