def lotus_root_data():
    """Tomographic X-ray data of a lotus root.

    Notes
    -----
    See the article `Tomographic X-ray data of a lotus root filled with
    attenuating objects`_ for further information.

    See Also
    --------
    lotus_root_geometry

    References
    ----------
    .. _Tomographic X-ray data of a lotus root filled with attenuating objects:
       https://arxiv.org/abs/1609.07299
    """
    # TODO: Store data in some ODL controlled url
    url = 'http://www.fips.fi/dataset/CT_Lotus_v1/sinogram.mat'
    dct = get_data('lotus_root.mat', subset=DATA_SUBSET, url=url)

    # Change axes to match ODL definitions
    data = np.swapaxes(dct['sinogram'], 0, 1)[:, :]
    data = data.astype('float')

    return data