1 files changed, 59 insertions, 0 deletions
diff --git a/Lib/turtledemo/chaos.py b/Lib/turtledemo/chaos.py
new file mode 100644
index 0000000..d4656f8
--- /dev/null
+++ b/Lib/turtledemo/chaos.py
@@ -0,0 +1,59 @@
+# File: tdemo_chaos.py
+# Author: Gregor Lingl
+# Date: 2009-06-24
+
+# A demonstration of chaos
+
+from turtle import *
+
+N = 80
+
+def f(x):
+    return 3.9*x*(1-x)
+
+def g(x):
+    return 3.9*(x-x**2)
+
+def h(x):
+    return 3.9*x-3.9*x*x
+
+def jumpto(x, y):
+    penup(); goto(x,y)
+
+def line(x1, y1, x2, y2):
+    jumpto(x1, y1)
+    pendown()
+    goto(x2, y2)
+
+def coosys():
+    line(-1, 0, N+1, 0)
+    line(0, -0.1, 0, 1.1)
+
+def plot(fun, start, colour):
+    pencolor(colour)
+    x = start
+    jumpto(0, x)
+    pendown()
+    dot(5)
+    for i in range(N):
+        x=fun(x)
+        goto(i+1,x)
+        dot(5)
+
+def main():
+    reset()
+    setworldcoordinates(-1.0,-0.1, N+1, 1.1)
+    speed(0)
+    hideturtle()
+    coosys()
+    plot(f, 0.35, "blue")
+    plot(g, 0.35, "green")
+    plot(h, 0.35, "red")
+    # Now zoom in:
+    for s in range(100):
+        setworldcoordinates(0.5*s,-0.1, N+1, 1.1)
+    return "Done!"
+
+if __name__ == "__main__":
+    main()
+    mainloop()