const int redPin=2;
const int yellowPin=3;
const int greenPin=4;
const char* redMessage = "Red light is on";
const char* yellowMessage = "Yellow light is on";
const char* greenMessage = "Green light is on";
void setup() {
  pinMode(redPin, OUTPUT);
  pinMode(yellowPin, OUTPUT);
  pinMode(greenPin, OUTPUT);
  Serial.begin(9600);
}

void loop() {

  digitalWrite(redPin, HIGH);
  Serial.println(redMessage);
  delay(15000);
  digitalWrite(redPin, LOW);


  digitalWrite(yellowPin, HIGH);
  Serial.println(yellowMessage);
  delay(15000);
  digitalWrite(yellowPin, LOW);


  digitalWrite(greenPin, HIGH);
  Serial.println(greenMessage);
  delay(15000);
  digitalWrite(greenPin, LOW);
}