save project

my_tree.py

 import turtle
 import turtle
+import random
 
 
 def tree(n):
 def tree(n):
-    if n>=50:
+    if n>=0:
+        pen.pensize(n/10)
         pen.forward(n)
         pen.forward(n)
-        pen.right(30)
-        tree(n-10)
-        pen.left(60)
-        tree(n-10)
-        pen.right(30)
+        angle = random.randint(0, 30)
+        length = random.randint(1,15)
+        pen.right(angle)
+        tree(n-length)
+        pen.left(2*angle)
+        tree(n-length)
+        pen.right(angle)
         pen.up()
         pen.up()
         pen.backward(n)
         pen.backward(n)
         pen.down()
         pen.down()
@@ -25,7 +29,7 @@ pen.up()
 pen.backward(150)    # 后退
 pen.backward(150)    # 后退
 pen.down()
 pen.down()
 
 
-tree(100)
+tree(60)
 
 
 turtle.done()
 turtle.done()