Using triple nested loops, a number pyramid is returned with periods and numbers printed on each line. The number of periods is determined by what line it is on. Line # - size = number of periods.

Triple Nested Loop

def triple_nested_loop(size):
    charlist = []
    numlist = []
    answer = ''
    sizelist = range(1,size)
    for dot in reversed(sizelist):
        charlist.append('.' * dot)
    for num in range(1,size+1):
        numlist.append(str(num) * num + '\n')
    for elem in range(len(numlist)):
        if elem == size-1:
            answer = answer + str(numlist[elem])
        else:
            answer = answer + charlist[elem] + str(numlist[elem])
    return answer