"""      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 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 "Laufzeit: %.3f sec" % (z1+et-at)

if __name__ == '__main__':

    msg = main()

    print msg

    mainloop()