save project

my_tree.py

 import turtle
-
+import random
 pen = turtle.Turtle()
 pen.color('sienna')
 # 画布大小
@@ -12,16 +12,29 @@ pen.left(90)
 # # pen.backward(150)    # 后退
 # pen.down()
 def tree(n):
-    if n>=50:
+    if n>=0:
         pen.forward(n)
-        pen.right(30)
-        pen.forward(n-10)
-        pen.backward(n-10)
-        pen.left(60)
-        pen.forward(n-10)
-        pen.backward(n-10)
-        pen.right(60)
-        tree(n-10)
-tree(100)
+        a=random.randint(0,30)
+        l=random.randint(1,15)
+        if l<=3:
+            pen.pencolor('snow')
+            pen.right(a)
+            tree(n-l)
+            pen.left(2*a)
+            tree(n-l)
+            pen.right(a)
+            pen.up()
+            pen.backward(n)
+            pen.down()
+        else:
+            pen.right(a)
+            tree(n-l)
+            pen.left(2*a)
+            tree(n-l)
+            pen.right(a)
+            pen.up()
+            pen.backward(n)
+            pen.down()
+tree(50)
 turtle.done()