"""This module contains a code example related to
Think Python, 2nd Edition
by Allen Downey
http://thinkpython2.com
Copyright 2015 Allen Downey
License: http://creativecommons.org/licenses/by/4.0/
"""
from __future__ import print_function, division
import math
import turtle
def draw_pie(t, n, r):
"""Draws a pie, then moves into position to the right.
t: Turtle
n: number of segments
r: length of the radial spokes
"""
polypie(t, n, r)
t.pu()
t.fd(r*2 + 10)
t.pd()
def polypie(t, n, r):
"""Draws a pie divided into radial segments.
t: Turtle
n: number of segments
r: length of the radial spokes
"""
angle = 360.0 / n
for i in range(n):
isosceles(t, r, angle/2)
t.lt(angle)
def isosceles(t, r, angle):
"""Draws an icosceles triangle.
The turtle starts and ends at the peak, facing the middle of the base.
t: Turtle
r: length of the equal legs
angle: peak angle in degrees
"""
y = r * math.sin(angle * math.pi / 180)
t.rt(angle)
t.fd(r)
t.lt(90+angle)
t.fd(2*y)
t.lt(90+angle)
t.fd(r)
t.lt(180-angle)
bob = turtle.Turtle()
bob.pu()
bob.bk(130)
bob.pd()
# draw polypies with various number of sides
size = 40
draw_pie(bob, 5, size)
draw_pie(bob, 6, size)
draw_pie(bob, 7, size)
draw_pie(bob, 8, size)
bob.hideturtle()
turtle.mainloop()