"""
 koch.py

 Using python's built in turtle to draw a Koch curve fractal.
 See https://en.wikipedia.org/wiki/Koch_snowflake .

 Jim Mahoney | cs.bennington.college | Oct 2020 | MIT License
"""
import turtle

def koch(length=400, recursionDepth=4):
    """ Recursively draw a Koch curve. """
    if recursionDepth == 0:
        turtle.forward(length)
    else:
        for angle in (0, 60, -120, 60):
            turtle.right(angle)
            koch(length/3.0, recursionDepth - 1)

def main():
    koch(380)    # length in pixels
    input('Hit return to quit.')  

main()