std::vector<GLint> Cube::BuildCube( bool face_top,
                                    bool face_bottom,
                                    bool face_front,
                                    bool face_back,
                                    bool face_left,
                                    bool face_right,
                                    int x, int y, int z)

if(face_top)
{
   std::vector elem = {xMin, yMax, zMin,
                       xMax, and so on...};
   output.insert(output.end, elem.begin(), elem.end());
}