Quake 2 models are made up of only triangles.
At offsetTriangles in the file is an array of triangle_t structures.
The array has numTriangles structures in it.
author  Johann Sorel

Size 3 :
These three shorts are indices into the array of vertices in each frames.
In other words, the number of triangles in a md2 file is fixed, and each
triangle is always made of the same three indices into each frame's array
of vertices. So, in each frame, the triangles themselves stay intact,
their vertices are just moved around.

Size 3 :
These three shorts are indices into the array of texture coordinates.