def generate_cartesian_coordinates(n_x, n_y, scaling=1.0):
    """
    Generate cartesian coordinates which can be used to set up a cell
    population.

    Parameters
    ----------
    n_x: int
        number of columns
    n_y: int
        number of rows
    scaling: float
        distance between the cells, in cell diameters
    """
    return [(scaling*i_x, scaling*i_y)
            for i_x in range(n_x) for i_y in range(n_y)
            ]