def tower_build(n_floors=1):
    """
    n_floors: number of floors for the tower
    return: tower consisting of "*" from top to bottom layed out as a pyramid
    """
    tower_list = ([" "*(n_floors-i) + "*"*(2*i-1) + " "*(n_floors-i) for i in range(1, n_floors+1)])
    return tower_list