def METHOD_NAME(indices):
    """
    This collapses together pairs of indices, so that
    the gaps in the volume array will have a zero width.
    """
    x, y, z = indices
    x[1::2, :, :] += 1
    y[:, 1::2, :] += 1
    z[:, :, 1::2] += 1
    return x, y, z