save project

my_tree.py

-import turtle
+import turtle,random
+pen=turtle.Pen()
+pen.color("sienna")
+sc=turtle.Screen()
+sc.bgcolor("wheat")
 
 
 pen = turtle.Turtle()
 pen = turtle.Turtle()
 pen.color('sienna')
 pen.color('sienna')
@@ -13,16 +17,25 @@ pen.backward(150)    # 后退
 pen.down()
 pen.down()
 
 
 def tree(n):
 def tree(n):
-    if n>=20:
+    if n>=0:
+        if n<15:
+            c=random.choice(["snow","lightcoral"])
+            pen.pencolor(c)
+            pen.pensize(5)
+        else:
+            pen.pencolor("sienna")
+            pen.pensize(n/10)
+        angle=random.randint(1,30)
+        length=random.randint(1,15)        
         pen.forward(n)
         pen.forward(n)
-        pen.right(30)
-        tree(n-20)
-        pen.left(60)
-        tree(n-20)
-        pen.right(30)
+        pen.right(angle)
+        tree(n-length)
+        pen.left(angle*2)
+        tree(n-length)
+        pen.right(angle)
         pen.penup()
         pen.penup()
         pen.backward(n)
         pen.backward(n)
         pen.pendown()
         pen.pendown()
-tree(100)
+tree(60)
 turtle.done()
 turtle.done()