save project

my_tree.py

+import turtle
+import random
+def tree(n):
+    if n>=0:
+        if n<=12:
+            d=['snow','lightcoral']
+            f=random.choice(d)
+            pen.color(f)
+            pen.pensize(n/3)
+        else: 
+            pen.color('sienna')      
+            pen.pensize(n/10)
+        pen.forward(n)
+        a=random.randint(1,30)
+        b=random.randint(1,15)
+        pen.right(a)
+        tree(n-b)
+        pen.left(2*a)
+        tree(n-b)
+        pen.right(a)
+        pen.up()
+        pen.backward(n)
+        pen.down()
+pen = turtle.Turtle()
+pen.color('sienna')
+pen.speed(0)
+# 画布大小
+w = turtle.Screen()
+w.bgcolor('wheat')  
+
+
+# 移动到起点
+pen.left(90)
+pen.up()
+pen.backward(150)    # 后退
+pen.down()
+tree(60)
+turtle.done()