short int ledPin[] = {12, 11, 10, 9, 8, 7, 6, 5, 4, 3};

void setup() {
  for(int i = 0; i < 10; i++){
    pinMode(ledPin[i], OUTPUT);
  }

}

void loop() {
  for(int i = 0; i < 10; i++){
    digitalWrite(ledPin[i], HIGH);
    delay(200);
    digitalWrite(ledPin[i], LOW);
  }

}