int redLed = 13;
int yellowLed = 12;
int greenLed = 11;

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

void loop() {
  // Green light ON for 5 seconds
  digitalWrite(greenLed, HIGH);
  delay(5000);

  // Green light OFF, Yellow light ON for 2 seconds
  digitalWrite(greenLed, LOW);
  digitalWrite(yellowLed, HIGH);
  delay(2000);

  // Yellow light OFF, Red light ON for 5 seconds
  digitalWrite(yellowLed, LOW);
  digitalWrite(redLed, HIGH);
  delay(5000);

  // Red light OFF, Yellow light ON for 2 seconds
  digitalWrite(redLed, LOW);
  digitalWrite(yellowLed, HIGH);
  delay(2000);

  // Yellow light OFF
  digitalWrite(yellowLed, LOW);
}