def METHOD_NAME(file_like, vertices_at_face):
    """Write triangular patches as OBJ faces.
    OBJ format uses vertex/UVtexture/normal; latter two left blank here.
    Parameters
    ----------
    file_like : file-like
        Opened file-like object to write faces to.
    vertices_at_face : array-like of int, shape *(n_faces, 3)*
        Vertex ids for each triangle.
    """
    for vertex_0, vertex_1, vertex_2 in vertices_at_face:
        print(f"f {vertex_0}// {vertex_1}// {vertex_2}//", file=file_like)