int buzzer=6;
void setup() {
  // 
  pinMode(13, OUTPUT);
  digitalWrite(13, LOW);
  pinMode(12, OUTPUT);
  digitalWrite(12, LOW);
  pinMode(11, OUTPUT);
  digitalWrite(11, LOW);
}

void loop() {
  // 
  digitalWrite(13, HIGH);
  delay(500);
  tone(buzzer, 13);
  digitalWrite(13, LOW);
  delay(500);
  tone(buzzer, 4);
  digitalWrite(12, HIGH);
  delay(500);
  tone(buzzer, 10);
  digitalWrite(12, LOW);
  delay(500);
  tone(buzzer, 9);
  digitalWrite(11, HIGH);
  delay(500);
  digitalWrite(11, LOW);
  delay(500);
  digitalWrite(6, HIGH);
  delay(500);
}