使用海龟绘图，输出4个300*300的矩形

import turtle
turtle.showturtle() #显示箭头，并绘制第一个300*300的矩形
turtle.goto(300,0)
turtle.goto(300,300)
turtle.goto(0,300)
turtle.goto(0,0)

turtle.penup() #绘制第二个300*300的矩形
turtle.goto(400,0)
turtle.pendown()
turtle.goto(700,0)
turtle.goto(700,300)
turtle.goto(400,300)
turtle.goto(400,0)

turtle.penup() #绘制第三个300*300的矩形
turtle.goto(0,-400)
turtle.pendown()
turtle.goto(300,-400)
turtle.goto(300,-100)
turtle.goto(0,-100)
turtle.goto(0,-400)

turtle.penup() #绘制第四个300*300的矩形
turtle.goto(400,-400)
turtle.pendown()
turtle.goto(700,-400)
turtle.goto(700,-100)
turtle.goto(400,-100)
turtle.goto(400,-400)