def triangles():
    n, list1, list2 = 0, [], [1]
    while True:
        for i in range(n):
            if i == n-1:
                list2.append(1)
            else:
                list2.append(list1[i] + list1[i+1])
        yield list2
        list1, list2 = list2, [1]
        n = n+1