static const int led[4] = {13, 12, 14, 27};


void setup() {
  for (int i = 0; i < 4; i++) {
    pinMode(led[i],OUTPUT);
  }

}

void loop() {
  for (int i = 0; i< 4;i++){
    digitalWrite(led[i],HIGH);  
    delay(1000);
  }
  for (int i = 0; i< 4;i++){
    digitalWrite(led[i],LOW); 
    delay(1000); 
  }
}