当按下按钮1时，流水灯以间隔时间500ms为单位，依次流水点亮（即按下按钮1后，灯1点亮500ms，其余灯熄灭。随后灯2点亮500ms, 其余灯熄灭. 随后灯3点亮500ms, 其余灯熄灭……）.任意时刻，当按钮2按下时，流水灯停止，并保持当前状态。-When the button is pressed 1, the light water units with an interval of 500ms, turn the water lit (ie press button 1, the lamp 1 lights 500ms, the rest of the lights go out. Subsequently lamp 2 lights 500ms, the remaining light goes out followed lamp 3 lights 500ms, the remaining lights off ......) any time, when button 2 is pressed, the light water stop, and maintain the current state.