def triangles():
    floor_0 = [1]
    yield floor_0
    floor_1 = [1, 1]
    yield floor_1
    triangles = [floor_0, floor_1]
    n = 2
    while True:
        floor_n_center = []
        for i in range(n - 1):     
            floor_n_center.append(triangles[n - 1][i] + triangles[n - 1][i + 1])
        floor_n = floor_0 + floor_n_center + floor_0
        triangles.append(floor_n)
        n += 1    
        yield floor_n