吴裕雄--天生自然python编程：turtle模块绘图（2）

#彩色螺旋线

import turtle
import time

turtle.pensize(2)
turtle.bgcolor("black")
colors = ["red", "yellow",'purple','blue']

turtle.tracer(False)

for x in range(400):
    turtle.forward(2*x)
    turtle.color(colors[x % 4])
    turtle.left(91)

turtle.tracer(True)

turtle.done()