graphics(
    vector_field_2d(sin(x - y), cos(x + y), (x, -3, 3), (y, -3, 3),
        streamlines=True, scalar=None,
        stream_kw={"density": 1.5},
        label="Magnitude of %s" % str([sin(x - y), cos(x + y)])),
    xlabel="x", ylabel="y", grid=False)
# Expected:
## Plot object containing:
## [0]: 2D vector series: [sin(x - y), cos(x + y)] over (x, -3.0, 3.0), (y, -3.0, 3.0)