const int yellowLight = 13;
const int greenLight = 12;
const int redLight = 11;



void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  pinMode(yellowLight, OUTPUT);
  pinMode(greenLight, OUTPUT);
  pinMode(redLight, OUTPUT);
  
  
  
  
  
}



void loop() {

  digitalWrite(redLight, HIGH);
  delay(2000);
  digitalWrite(yellowLight, HIGH);
  digitalWrite(redLight, LOW);
  delay(2000);
  digitalWrite(yellowLight, LOW);
  digitalWrite(greenLight, HIGH);
  delay(4000);
  digitalWrite(greenLight, LOW);

 



}