save project

my_tree.py

+import turtle
+import random
+
+pen = turtle.Turtle()
+pen.color('sienna')
+# 画布大小
+w = turtle.Screen()
+w.bgcolor('wheat')      # wheat小麦
+
+# 移动到起点
+pen.left(90)
+pen.up()
+pen.backward(150)    # 后退
+pen.down()
+
+def tree(n):
+    if n>=20:
+        angle=random.randint(10,30)
+        length=random.randint(10,15)
+        pen.forward(n)
+        pen.right(angle)
+        tree(n-length)
+        pen.left(angle*2)
+        tree(n-length)
+        pen.right(angle)
+        pen.penup()
+        pen.forward(-n)
+        pen.pendown()
+
+tree(100)
+turtle.done()