save project

my_tree.py

@@ -13,7 +13,7 @@ pen.backward(150)    # 后退
 pen.down()
 pen.speed(1000)
 def tree(n):
-    if n>=0:
+    if n>=50:
         pen.forward(n)
         pen.right(30)
         tree(n-20)
@@ -23,5 +23,5 @@ def tree(n):
         pen.up()
         pen.backward(n)
         pen.down()
-tree(100)
+tree(150)
 turtle.done()