save project

my_tree.py

+import turtle
+import random
+pen = turtle.Turtle()
+pen.color('red')
+pen.speed(0)
+pen.left(90)
+w = turtle.Screen()
+w.bgcolor('black')
+pen.pu()      
+pen.backward(150)
+pen.pd()# wheat小麦
+def tree(n): 
+    if n>50:
+        ag=random.randint(0,120)
+        le=random.randint(1,40)
+        pen.pensize(n/20)
+        pen.fd(ag)
+        pen.right(le)
+        tree(n-10)
+        pen.left(2*le)
+        tree(n-10)
+        pen.right(le)
+
+        
+        pen.pu()
+        pen.backward(ag)
+        pen.pd()
+    
+        
+print(tree(100))
+        
+    # 移动到起点
+    #pen.left(90)
+    #pen.fd(100)
+    #pen.left(30)
+    #pen.fd(100)
+    #pen.up()
+    #pen.backward(100) 
+    #pen.pd()
+    #pen.right(60)
+    #pen.fd(100)
+    #pen.pu()
+    #pen.backward(100)   # 后退
+    #pen.down()
+
+turtle.done()