const int dotDuration = 250;
const int dashDuration = 3 * dotDuration;

void setup() {
  pinMode(5, OUTPUT);
}

void loop() {
  char letter[] = {'.', '.', '.', '.'};
  
  for (int i = 0; i < sizeof(letter); i++) {
    if (letter[i] == '.') {
      digitalWrite(5, HIGH);
      delay(dotDuration);
    } else if (letter[i] == '-') {
      digitalWrite(5, HIGH);
      delay(dashDuration);
    }
    digitalWrite(5, LOW);
    delay(dotDuration);
  }
  exit(0);
}