说明书：https://docs.python.org/3/

import turtle
# import 导入   turtle 一个名字叫乌龟的画画工具包
# 注释 并不会运行
# forward 向前走  ：长度
turtle.forward(100)
# 左 left   右 right：角度
turtle.left(120)
turtle.forward(120)
# 抬笔 pen up
turtle.penup()
# 过去 goto()
turtle.goto(100, 100)
# 落笔
turtle.pendown()
turtle.forward(120)
# 圆 circle: 半径
turtle.circle(120)


# do 做 过去完成时 done
turtle.done()


import turtle
turtle.forward(100)
turtle.left(90)
turtle.forward(100)
turtle.left(90)
turtle.forward(100)
turtle.left(90)
turtle.forward(100)
turtle.left(90)
turtle.penup()
turtle.goto(-30,-30)
turtle.pendown()
turtle.forward(100)
turtle.left(90)
turtle.forward(100)
turtle.left(90)
turtle.forward(100)
turtle.left(90)
turtle.forward(100)