3 2 # <vertex #> <x> <y> [attributes] ...Triangulation Vertices...
0 0.0 0.0 0.0 0.0 
1 0.0 5.0 5.0 10.0 
2 5.0 0.0 5.0 10.0 
1 # <triangle #> [<vertex #>] [<neigbouring triangle #>] [attribute of region] ...Triangulation Triangles...
0 0 2 1 -1 -1 -1  ['']
3 # <segment #> <vertex #>  <vertex #> [boundary marker] ...Triangulation Segments...
0 0 1 external
1 2 0 external
2 1 2 external