Python 画四个圆

import turtle # 导入turtle
turtle.title("画圆")
pen = turtle.Pen()

pen.pencolor("red")
pen.pensize(1)

pen.circle(100)
pen.pencolor("yellow")
pen.circle(-100)
pen.setheading(90)
pen.pencolor("blue")
pen.circle(100)
pen.pencolor("purple")
pen.circle(-100)

turtle.done