bpo-14117: Make minor tweaks to turtledemo (GH-8002)

The 'wikipedia' example is now 'rosette', describing what it draws.
The 'penrose' print output is reduced.  The 'tree' '1024'
output is eliminated.
(cherry picked from commit 891a1f86d415779cf67ca23e626a868e586feb05)

Co-authored-by: Terry Jan Reedy <tjreedy@udel.edu>

1 files changed, 65 insertions, 0 deletions

diff --git a/Lib/turtledemo/rosette.py b/Lib/turtledemo/rosette.py
new file mode 100644
index 0000000..0f27442
--- /dev/null
+++ b/Lib/turtledemo/rosette.py
@@ -0,0 +1,65 @@
+"""      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 "runtime: %.3f sec" % (z1+et-at)
+
+
+if __name__ == '__main__':
+    msg = main()
+    print(msg)
+    mainloop()