save project

d2.py

 import turtle
 pen = turtle.Pen()
- 
+b=turtle.Screen()
+b.bgcolor("Sky blue")
+colors=["red","orange","yellow","green"] 
 pen.speed(100)
 for i in range(1,400):
     pen.forward(i)
-    
+    pen.pencolor(colors[i%4])
     pen.right(91)
 pen.hideturtle()
 turtle.done()