const int leds[] = {15, 2, 4, 5, 18, 19, 21, 22};

void setup() {
  
  for (int i = 0; i < 8; i++) {
    pinMode(leds[i], OUTPUT);
  }
}

void loop() {

  for (int i = 0; i < 8; i++) {
    digitalWrite(leds[i], HIGH);
  }
  delay(800);

  for (int i = 0; i < 8; i++) {
    digitalWrite(leds[i], LOW);
  }
  delay(2000);
}