实现相邻两个LED指示灯依次从左至右显示，到最左端，再依次从右至左显示，到最右端，再依次从左至右显示，周而复始。

LED指示灯显示到两顶端时，都使蜂鸣器发出响声。之后，再改变显示方向。LED指示灯第一次显示之前，蜂鸣器先发出响声。之后，再依次从左至右显示。

-⑴ achieve two adjacent LED light show from left to right order, to the extreme left, then turn right to the left shows that the most right side, and then followed by shows from left to right again and again. ⑵ LED indicator light shows that the top two, they make noise buzzer. After changing the display direction. LED indicator light shows the first time before the first buzzer noise. After the show in order from left to right.