const int redPins[] = {27,18,22,13};
const int yellowPins[] = {14,2,17,21};
const int greenPins[] = {25,15,19,4};

void setup() {
  for (int i = 0; i < 4; i++) {
    pinMode(redPins[i], OUTPUT);
    pinMode(yellowPins[i], OUTPUT);
    pinMode(greenPins[i], OUTPUT);
  }
}

void loop() {
 
  setLights(redPins, HIGH);
  delay(2000);
  
 
  setLights(redPins, LOW);
  setLights(yellowPins, HIGH);
  delay(1000);
  
 
  setLights(yellowPins, LOW);
  setLights(greenPins, HIGH);
  delay(3000);
  
  setLights(greenPins, LOW);
  setLights(yellowPins, HIGH);
  delay(1000);
  
 
  setLights(yellowPins, LOW);
  delay(1000);
}

void setLights(const int pins[], int state) {
  for (int i = 0; i < 4; i++) {
    digitalWrite(pins[i], state);
  }
}