""" turtle-example-suite:

 tdemo_wikipedia3.py

This example is
inspired by the Wikipedia article on turtle
graphics. (See example wikipedia1 for URLs)

First we create (ne-1) (i.e. 35 in this
example) copies of our first turtle p.
Then we let them perform their steps in
parallel.

Followed by a complete undo().
"""
from turtle import Screen, Turtle, mainloop
from time import perf_counter as clock, sleep

def mn_eck(p, ne,sz):
 turtlelist = [p]
 #create ne-1 additional turtles
 for i in range(1,ne):
 q = p.clone()
 q.rt(360.0/ne)
 turtlelist.append(q)
 p = q
 for i in range(ne):
 c = abs(ne/2.0-i)/(ne*.7)
 # let those ne turtles make a step
 # in parallel:
 for t in turtlelist:
 t.rt(360./ne)
 t.pencolor(1-c,0,c)
 t.fd(sz)

def main():
 s = Screen()
 s.bgcolor("black")
 p=Turtle()
 p.speed(0)
 p.hideturtle()
 p.pencolor("red")
 p.pensize(3)

 s.tracer(36,0)

 at = clock()
 mn_eck(p, 36, 19)
 et = clock()
 z1 = et-at

 sleep(1)

 at = clock()
 while any(t.undobufferentries() for t in s.turtles()):
 for t in s.turtles():
 t.undo()
 et = clock()
 return "runtime: %.3f sec" % (z1+et-at)


if __name__ == '__main__':
 msg = main()
 print(msg)
 mainloop()