"""
Simple generators
by K. Urner
4D Solutions
"""

def pascal():
    """generate rows of Pascal's Triangle"""
    row = [1]
    while True:
        yield row
        row = [i+j for i,j in zip(row + [0], [0] + row)]

def fibo():
    """generate Fibonacci sequence"""
    a,b = 0,1
    while True:
        yield a
        a,b = b, a+b