int red = 13;
int yellow = 12;
int green = 11;

void setup() {
  // put your setup code here, to run once:
  pinMode(red,OUTPUT);
  pinMode(yellow,OUTPUT);
   pinMode(green,OUTPUT);


}

void loop() {
  // put your main code here, to run repeatedly:
  digitalWrite(red,HIGH);
  digitalWrite(yellow,HIGH);
  digitalWrite(green,LOW);
  delay(1500);
  
 digitalWrite(red,LOW);
  digitalWrite(yellow,HIGH);
  digitalWrite(green,LOW);
  delay(1500);
  
   digitalWrite(red,LOW);
  digitalWrite(yellow,LOW);
  digitalWrite(green,HIGH);
  delay(1500);
   
    digitalWrite(red,HIGH);
  digitalWrite(yellow,LOW);
  digitalWrite(green,LOW);
  delay(1500);
  
}