1"""      turtle-example-suite:
2
3          tdemo_wikipedia3.py
4
5This example is
6inspired by the Wikipedia article on turtle
7graphics. (See example wikipedia1 for URLs)
8
9First we create (ne-1) (i.e. 35 in this
10example) copies of our first turtle p.
11Then we let them perform their steps in
12parallel.
13
14Followed by a complete undo().
15"""
16from turtle import Screen, Turtle, mainloop
17from time import clock, sleep
18
19def mn_eck(p, ne,sz):
20    turtlelist = [p]
21    #create ne-1 additional turtles
22    for i in range(1,ne):
23        q = p.clone()
24        q.rt(360.0/ne)
25        turtlelist.append(q)
26        p = q
27    for i in range(ne):
28        c = abs(ne/2.0-i)/(ne*.7)
29        # let those ne turtles make a step
30        # in parallel:
31        for t in turtlelist:
32            t.rt(360./ne)
33            t.pencolor(1-c,0,c)
34            t.fd(sz)
35
36def main():
37    s = Screen()
38    s.bgcolor("black")
39    p=Turtle()
40    p.speed(0)
41    p.hideturtle()
42    p.pencolor("red")
43    p.pensize(3)
44
45    s.tracer(36,0)
46
47    at = clock()
48    mn_eck(p, 36, 19)
49    et = clock()
50    z1 = et-at
51
52    sleep(1)
53
54    at = clock()
55    while any([t.undobufferentries() for t in s.turtles()]):
56        for t in s.turtles():
57            t.undo()
58    et = clock()
59    return "Laufzeit: %.3f sec" % (z1+et-at)
60
61
62if __name__ == '__main__':
63    msg = main()
64    print msg
65    mainloop()
66