save project

my_tree.py

+import turtle
+
+pen = turtle.Turtle()
+pen.color('sienna')
+# 画布大小
+w = turtle.Screen()
+w.bgcolor('wheat')      # wheat小麦
+def tree(n,m,a):
+    if n>=50:
+        pen.pensize(n//10)
+        pen.forward(n)
+        pen.right(a)
+        tree(n-m,m,a)
+        pen.left(a*2)
+        tree(n-m,m,a)
+        pen.right(a)
+        pen.up()
+        pen.backward(n)
+        pen.down()
+# 移动到起点
+pen.left(90)
+pen.up()
+pen.backward(150)    # 后退
+pen.down()
+
+
+tree(100,10,30)
+turtle.done()