左右pili

 int led[]={2,3,4,5,6,7,8,9};

int j=0;

int x=0;

void setup() {

  // put your setup code here, to run once:

  for(int i=0;i<=7;i++)

  {

    pinMode(led[i],OUTPUT);

  }

}

void loop() {

  // put your main code here, to run repeatedly:

  if(x==0)

  {

    for(int i=0;i<=7;i++)

    {

      digitalWrite(led[i],LOW);

    }

    digitalWrite(led[j],HIGH);  delay(1000);

    digitalWrite(led[j],LOW);

    j++;

    if(j==7) x=1;

  }

  if(x==1)

  {

    for(int i=7;i>=0;i--)

    {

      digitalWrite(led[i],LOW);

    }

    digitalWrite(led[j],HIGH);  delay(1000);

    digitalWrite(led[j],LOW);

    j--;

    if(j==0) x=0;

  }

}