#define red 5
#define green 4
#define yellow 3
#define buzzer 9

void setup() {
 
  pinMode(red,    OUTPUT);
  pinMode(green,  OUTPUT);
  pinMode(yellow, OUTPUT);
  pinMode(buzzer, OUTPUT);
}

void loop() {
  digitalWrite(red,    HIGH);
  digitalWrite(green,  LOW);
  digitalWrite(yellow, LOW);
  delay(5000);
  
  digitalWrite(red,    LOW);
  digitalWrite(yellow, HIGH);
  digitalWrite(green,  LOW);
  tone(buzzer,HIGH);
  delay(5000);
  noTone(buzzer);
  
  digitalWrite(red,   LOW);
  digitalWrite(green, HIGH);
  digitalWrite(yellow,LOW);
  delay(5000);

  
}