def make_variable_names_with_time_steps(number_of_lags, data_column_names):
    """
    lagged W first, instantaneous W last, i.e.,

    ..., x1_{t-2}, x2_{t-2}, ..., x1_{t-1}, x2_{t-1}, ..., x1_{t}, x2_{t}, ...
    """
    variable_names = []
    for i in range(number_of_lags, 0, -1):
        variable_names_lagged = [s + '(t-{})'.format(i) for s in data_column_names]
        variable_names += variable_names_lagged

    variable_names_t = [s + '(t)' for s in data_column_names]
    variable_names += variable_names_t

    return variable_names