save project

diy1.py

@@ -3,9 +3,12 @@
 每次移动都增加画笔移动的长度，并旋转91°，重复执行300次，查看效果
 """
 import turtle
-
+screen=turtle.Screen()
+screen.bgcolor("black")
+color=["green","red","orange","yellow"]
 pen=turtle.Pen()
 for i in range(1,300):
+    pen.pencolor(color[i%4])
     pen.forward(i)
     pen.right(91)
 pen.hideturtle()