auto save

snake.py

@@ -20,6 +20,9 @@ while True:
         if event.type == locals.QUIT:
             # 接收到退出事件后退出程序
             exit()
+    for i in range(len(position)-1):
+        screen.blit(body, position[i])
+
     x+=30
     position.append((x,y))
     position.pop(0)