# centipede.py

from turtle import *

# show a centipede-like thing moving around the screen
def centipede(length, step, life):
    # lift the pen so no drawing happens
    penup()
    theta = 0
    dtheta = 1
    for i in range(life):
        forward(step)
        left(theta)
        theta += dtheta
        # draw a picture of a turtle
        stamp()
        if i > length:
            clearstamps(1)
        if theta > 10 or theta < -10:
            dtheta = -dtheta
        if ycor() > 350:
            left(30)

# draw a star on the screen
def star():
    color('red', 'yellow')
    begin_fill()
    hideturtle()
    while True:
        forward(200)
        left(170)
        if abs(pos()) < 1:
            break
    end_fill()

def square(side):
    pendown()
    for i in range(4):
        forward(side)
        left(90)

def triangle(side):
    pendown()
    for i in range(3):
        forward(side)
        left(120)
    
def main():
    setworldcoordinates(-400, -400, 400, 400)
    ask = input("Centipede (c) or star (s)? ")
    if ask == "c":
        centipede(14, 10, 200)
    elif ask == "s":
        star()
    elif ask == "q":
        square(50)
    else:
        triangle(50)
    exitonclick()

main()