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
+
+def tree(n):
+    if n >= 0 :
+        if n<=12:
+            pen.color(random.choice(["snow","lightcoral"]))
+            pen.pensize(n/3)
+        else:
+            pen.pensize(n/10)
+            pen.color('sienna')
+        pen.speed(100)
+        pen.forward(n)
+        angle = random.randint(0,30)
+        length = random.randint(1,15)
+        pen.right( angle )
+        tree(n-length)
+        pen.left(2 * angle)
+        tree(n-length)
+        pen.penup()
+        pen.right(angle)
+        pen.backward(n)
+        pen.down()
+
+# 移动到起点
+pen.left(90)
+pen.up()
+pen.backward(150)    # 后退
+pen.down()
+tree(60)
+
+turtle.done()