用turtle库绘制图形(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, color):
    pencolor(color)
    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()