MiliTriStripper groups the triangles of a 3D model into triangle strips.
What can it be useful for to group triangles into triangle strips?
— You can make smaller file size when you store your triangles into a file!
Finding the best grouping to group triangles into triangle strips is
a NP-hard problem.
Read
NP-hardness and
NP (complexity)
on Wikipedia.
(here an example of strippification: screenshot)