画图不是很清楚,看了一位同学的代码 链接：https://blog.csdn.net/weixin_43212500/article/details/89196024
import turtle
from random import *
from math import *
def tree(n,l):
turtle.pd()#下笔
#阴影效果
t = cos(radians(turtle.heading()+45))/8+0.25
turtle.pencolor(t,t,t)
turtle.pensize(n/3)
turtle.forward(l)#画树枝
if n>0:
b = random()*15+10 #右分支偏转角度
c = random()*15+10 #左分支偏转角度
d = l*(random()*0.25+0.7) #下一个分支的长度
#右转一定角度,画右分支
turtle.right(b)
tree(n-1,d)
#左转一定角度，画左分支
turtle.left(b+c)
tree(n-1,d)
#转回来
turtle.right(c)
else:
#画叶子
turtle.right(90)
n=cos(radians(turtle.heading()-45))/4+0.5
turtle.pencolor(n,n*0.8,n*0.8)
turtle.circle(3)
turtle.left(90)
#添加0.3倍的飘落叶子
if(random()>0.7):
turtle.pu()
#飘落
t = turtle.heading()
an = -40 +random()*40
turtle.setheading(an)
dis = int(800*random()*0.5 + 400*random()*0.3 + 200*random()*0.2)
turtle.forward(dis)
turtle.setheading(t)
#画叶子
turtle.pd()
turtle.right(90)
n = cos(radians(turtle.heading()-45))/4+0.5
turtle.pencolor(n*0.5+0.5,0.4+n*0.4,0.4+n*0.4)
turtle.circle(2)
turtle.left(90)
turtle.pu()
#返回
t=turtle.heading()
turtle.setheading(an)
turtle.backward(dis)
turtle.setheading(t)
turtle.pu()
turtle.backward(l)#退回
turtle.bgcolor(0.5,0.5,0.5)#背景色
turtle.ht()#隐藏turtle
turtle.speed(0)#速度 1-10渐进，0 最快
turtle.tracer(0,0)
turtle.pu()#抬笔
turtle.backward(100)
turtle.left(90)#左转90度
turtle.pu()#抬笔
turtle.backward(300)#后退300
tree(12,100)#递归7层
turtle.done()