my_tree.py

import turtle

def tree(n):
    if 50>= 50:       
    pen.fd(100)
    pen.right(30)
    tree(n-50)
    
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()

turtle.done()