def METHOD_NAME(nb_streamlines=1, nb_pts=30, step_size=1,
                         delta=1):
    bundle = []
    bundle_length = step_size * nb_pts
    Z = np.linspace(0, bundle_length, nb_pts)
    for x in delta*np.arange(0, nb_streamlines):
        Xk = np.ones(nb_pts) * x
        Yk = np.zeros(nb_pts)
        Zk = Z.copy()
        bundle.append(np.c_[Xk, Yk, Zk])
    return bundle