const int redLed = 2;
const int yellowLed = 3;
const int greenLed = 4;
const int buzzer = 5;

void setup() {
  pinMode(redLed, OUTPUT);
  pinMode(yellowLed, OUTPUT);
  pinMode(greenLed, OUTPUT);
  pinMode(buzzer, OUTPUT);
}

void loop() {
  digitalWrite(redLed, HIGH);
  digitalWrite(yellowLed, LOW);
  digitalWrite(greenLed, LOW);
  tone(buzzer, 1000);
  delay(500);

  digitalWrite(redLed, LOW);
  digitalWrite(yellowLed, HIGH);
  digitalWrite(greenLed, LOW);
  tone(buzzer, 1200);
  delay(500);

  digitalWrite(redLed, LOW);
  digitalWrite(yellowLed, LOW);
  digitalWrite(greenLed, HIGH);
  tone(buzzer, 1400);
  delay(500);

  noTone(buzzer);
}