save project

my_tree.py

+import turtle
+import random
+pen = turtle.Turtle()
+pen.color('sienna')
+
+
+def tree(n):
+    if n >= 10:
+        a = random.randint(0,50)
+        b = random.randint(4,15)
+
+        if n < 20:
+            pen.color(random.choice(['snow','lightcoral']))
+            pen.pensize(n/3)
+        else:
+            pen.color('sienna')
+            pen.pensize(n/15)
+        pen.forward(a)
+        pen.right(b)
+        tree(n-10)
+        pen.left(2*b)
+        tree(n-10)
+        pen.right(b)
+        pen.up()
+        pen.backward(a)
+        pen.down()
+# 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(200)    # 后退
+pen.down()
+tree(100)
+turtle.done()