save project

snake.py

@@ -60,10 +60,10 @@ while True:
         a=random.randint(0,15)*30
     else:
         position.pop(0)
+    if x > 0 or x > 630 or y < 0 or y >450: 
+        exit()
     # 将背景图画上去
-    
     screen.blit(background, (0, 0))
-    
     # 将贪吃蛇的头画上去
     screen.blit(snake_head, position[-1])
     # 将贪吃蛇的身体画上去