int dotDelay = 300;

void setup() {
 pinMode(2, OUTPUT);
 pinMode(3, OUTPUT);
 pinMode(4, OUTPUT);
 pinMode(5, OUTPUT);
 pinMode(6, OUTPUT);
}

void loop() {

  // Light up 0 in Morse code (-----)
  for (int i = 2; i < 7; i++) {
    digitalWrite(i, HIGH);
    delay(dotDelay * 3);
    digitalWrite(i, LOW);
    delay(dotDelay*2); //Delay between LED
  }
  delay(dotDelay * 3); //Delay between numbers


  //Light up 4 in Morse code (....-)
  for (int i = 2; i < 6; i++) {
    digitalWrite(i, HIGH);
    delay(dotDelay);
    digitalWrite(i, LOW);
    delay(dotDelay*2); //Delay between LED
  }

  for (int i = 6; i < 7; i++) {
  digitalWrite(i, HIGH);
  delay(dotDelay * 3);
  digitalWrite(i, LOW);
  delay(dotDelay * 2); //Delay between LED
  }
  delay(dotDelay * 3); //Delay between numbers
}