save project

snake.py

@@ -62,7 +62,9 @@ while True:
         ns+= 1
     else:
         position.pop(0) 
-     
+    if x < 0 or x > 630 or y < 0 or y >450:
+        
+
     # 将背景图画上去
     screen.blit(background, (0, 0))
     # 将贪吃蛇的头画上去