void setup() {
  // put your setup code here, to run once:
  for (int i = 8; i <= 13; ++i)
    pinMode(i, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  digitalWrite(8, LOW);
  digitalWrite(9, LOW);

  delay(500);

  digitalWrite(8, HIGH);
  digitalWrite(9, HIGH);

  delay(500);
}