def METHOD_NAME(ts, coor, **kwargs):
    from sfepy.linalg import rotation_matrix2d
    vec = coor[:,1:3] - centre
    angle = 10.0 * ts.step
    print('angle:', angle)
    mtx = rotation_matrix2d( angle )
    vec_rotated = nm.dot( vec, mtx )
    displacement = vec_rotated - vec
    return displacement