int pinLED[] = {21, 22, 23, 25, 26, 27, 32, 33};

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

void loop() {
  for (int i=0; i < 8; i++) {
  digitalWrite(pinLED[i], HIGH);
  delay(200);
  digitalWrite(pinLED[i], LOW);
  delay(200);
}
}