int lights[] = {13, 12, 14, 27, 23, 22, 21, 19};

void setup() {
  // initialization of pins to the leds
  for(int i=0; i < 8; i++) {
    pinMode(lights[i], OUTPUT);
  }
}

void loop() {
  // cycling through each light and turning it on and off
  for(int i=0; i < 8; i++) {
    digitalWrite(lights[i], HIGH);
    delay(500); 
    digitalWrite(lights[i], LOW);
  } 
}