def incremental_marker(count, interval=5, range_start=0):
    """
    Return back a visual marker if the counter lands on a multiple of
    a specified interval. This is meant to append to results output
    when processing an iterator.
    
    :param count: integer containing counter number
    :param interval: integer containing the interval to which counter 
                     should be compared
    :param range_start: start position of range that counter is incrementing
                        through. For example 0 means it is a 0 index based
                        range, so a counter of 2 would represent the 3rd
                        item in a list.
    :return: string with marker value
    """
    position = count + 1 - range_start
    return "*" if position % interval == 0 else " "