save project

diy1.py

 
 import turtle
 pen = turtle.Pen()
+screen=turtle.Screen()
+screen.bgcolor("black")
+colors=["red","green","yellow","blue"]
 for i in range(1,300):
-    pen.forward(i)
-    i+=1
+    pen.pencolor(colors[i%4])
+    pen.forward(i)    
     pen.right(91)
-# 隐藏画笔，保存画布
 pen.hideturtle()
 turtle.done()
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