def init():
        im1.set_data(XYslice[0, :, :])
        im2.set_data(XZslice[0, Nplans/2:, :])
        return([im1, im2])

    def animate(t):
       im1.set_data(XYslice[t, :, :])
       im2.set_data(XZslice[t, Nplans/2:, :])
       return [im1, im2]

    anim = animation.FuncAnimation(fig, animate, np.arange(Ntime), interval=200,
                                 blit=True, init_func=init, repeat=True)