GML
d3d_primitive_begin(pr_linelist);
d3d_vertex( x1_1, y1_1, z1_1 );
d3d_vertex( x2_1, y2_1, z2_1 );
d3d_vertex( x1_2, y1_2, z1_2 );
d3d_vertex( x2_2, y2_2, z2_2 );
d3d_vertex( x1_3, y1_3, z1_3 );
d3d_vertex( x2_3, y2_3, z2_3 );
// etc.
d3d_primitive_end();
:)