def points_from_x0y0x1y1(xyxy):
    """
    Constructs a polygon representation from a rectangle described as a list [x0, y0, x1, y1]
    """
    [x0, y0, x1, y1] = xyxy
    return "%s,%s %s,%s %s,%s %s,%s" % (
        x0, y0,
        x1, y0,
        x1, y1,
        x0, y1
    )