#define RED_LIGHT 0     
#define YELLOW_LIGHT 1  
#define GREEN_LIGHT 2 

void setup() {
  // Set pins as outputs
  pinMode(RED_LIGHT, OUTPUT);
  pinMode(YELLOW_LIGHT, OUTPUT);
  pinMode(GREEN_LIGHT, OUTPUT);
}

void loop() {
  digitalWrite(RED_LIGHT, HIGH);
  digitalWrite(YELLOW_LIGHT, HIGH);
  digitalWrite(GREEN_LIGHT, LOW);
  delay(3000);

  digitalWrite(RED_LIGHT, HIGH);
  digitalWrite(YELLOW_LIGHT, LOW);
  digitalWrite(GREEN_LIGHT, HIGH);
  delay(1000);

  digitalWrite(RED_LIGHT, LOW);
  digitalWrite(YELLOW_LIGHT, HIGH);
  digitalWrite(GREEN_LIGHT, HIGH);
  delay(3000);

  
  digitalWrite(RED_LIGHT, HIGH);
  digitalWrite(YELLOW_LIGHT, HIGH);
  digitalWrite(GREEN_LIGHT, HIGH);
  delay(100);

  digitalWrite(RED_LIGHT, LOW);
  digitalWrite(YELLOW_LIGHT, HIGH);
  digitalWrite(GREEN_LIGHT, HIGH);
  delay(100);

  digitalWrite(RED_LIGHT, HIGH);
  digitalWrite(YELLOW_LIGHT, HIGH);
  digitalWrite(GREEN_LIGHT, HIGH);
  delay(100);

  digitalWrite(RED_LIGHT, LOW);
  digitalWrite(YELLOW_LIGHT, HIGH);
  digitalWrite(GREEN_LIGHT, HIGH);
  delay(100);

  digitalWrite(RED_LIGHT, HIGH);
  digitalWrite(YELLOW_LIGHT, HIGH);
  digitalWrite(GREEN_LIGHT, HIGH);
  delay(100);

  digitalWrite(RED_LIGHT, LOW);
  digitalWrite(YELLOW_LIGHT, HIGH);
  digitalWrite(GREEN_LIGHT, HIGH);
  delay(100);
}