import turtle

pen = turtle.Turtle()
pen.color('sienna')
# 画布大小
w = turtle.Screen()
w.bgcolor('wheat')      # wheat小麦

# 移动到起点
pen.left(90)
pen.up()
pen.backward(150)    # 后退
pen.down()
def zhu(zhu_):
    if zhu_>=50:
        pen.forward(zhu_)
        pen.right(30)
        zhu(zhu_-10)
        pen.left(60)
        zhu(zhu_-10)
        pen.penup()
        pen.right(30)
        pen.backward(zhu_)
        pen.pendown()

zhu(100)
turtle.done()