def faces_indices_vectors_to_matrix(indices, faces):
    """faces_indices_vectors_to_matrix(indices, faces) -> List[List[int]]
    PyPRT outputs the GeneratedModel face information as a list of vertex indices 
    and a list of face indices count. This function converts these two lists into 
    one list of lists containing the vertex indices per face.

    Parameters:
        indices: List[int]
        faces: List[int]

    Returns:
        List[List[int]]

    Example:
        ``[[1, 0, 3, 2], [4, 5, 6, 7], [0, 1, 5, 4], [1, 2, 6, 5], [2, 3, 7, 6], [3, 0, 4, 7]] 
        = faces_indices_vectors_to_matrix(([1, 0, 3, 2, 4, 5, 6, 7, 0, 1, 5, 4, 1, 2, 6, 5, 
        2, 3, 7, 6, 3, 0, 4, 7],[4, 4, 4, 4, 4, 4]))``
    """
    faces_as_matrix = []
    offset = 0
    for f in faces:
        ind_per_face = indices[offset:offset+f]
        offset += f
        faces_as_matrix.append(ind_per_face)
    return faces_as_matrix