// Pin definitions for LEDs
const int redLED = 9;
const int yellowLED = 7;
const int greenLED = 8;

void setup() {
  // Set LED pins as output
  pinMode(redLED, OUTPUT);
  pinMode(yellowLED, OUTPUT);
  pinMode(greenLED, OUTPUT);
}

void loop() {

  // GREEN ON → YELLOW OFF → RED OFF
  digitalWrite(greenLED, HIGH);
  digitalWrite(yellowLED, LOW);
  digitalWrite(redLED, LOW);
  delay(2000);

  // GREEN OFF → YELLOW ON → RED OFF
  digitalWrite(greenLED, LOW);
  digitalWrite(yellowLED, HIGH);
  digitalWrite(redLED, LOW);
  delay(1000);

  // GREEN OFF → YELLOW OFF → RED ON
  digitalWrite(greenLED, LOW);
  digitalWrite(yellowLED, LOW);
  digitalWrite(redLED, HIGH);
  delay(2000);
}