auto save

.py

@@ -3,11 +3,13 @@ import turtle
 pen = turtle.Pen()
 pen.shape("turtle")
 pen.shapesize(10)
-
-for i in range(0,300,1):
+s=turtle.Screen()
+s.bgcolor("grey")
+c=["black","red","purple","blue"]
+for i in range(300):
     pen.forward(i)
     pen.right(91)
-
+    pen.pencolor(c[i%4])
 
 # 隐藏画笔，保存画布
 pen.hideturtle()