def vertices_frame(size, frame_thickness):
    """Returns a list of vertices describing a frame

    Notes
    -----
    The resulting vertices can be plotted with the class
    stimuli.Shape(vertex_list=...).

    Parameters
    ----------
    size : (int, int)
        size (width, height) of the rectangle
    frame_thickness : int
        the thickness of the frame

    Returns
    -------
    vtx : list of vertices

    """
    return [(size[0] - frame_thickness - 1, 0), (0, -size[1] + 1), (-size[0
        ] + 1, 0), (0, size[1] - 1), (frame_thickness - 1, 0), (0, -(size[1
        ] - frame_thickness - 1)), (size[0] - 2 * frame_thickness - 1, 0),
        (0, size[1] - 2 * frame_thickness - 1), (-(size[0] - 2 *
        frame_thickness - 2), 0)]
