void setup() {
  // put your setup code here, to run once:
  pinMode(13, OUTPUT); //red LED 10 sec
  pinMode(12, OUTPUT); //green LED 12 sec
  pinMode(11, OUTPUT); //yellow LED 3 sec

  Serial.begin(9600);  //serial monitor //essential to detect distance and reveal value

}

void loop() {
  // put your main code here, to run repeatedly:
  for (int red = 10; red>=0; red--) {
  digitalWrite(13, HIGH);
  digitalWrite(12, LOW);
  digitalWrite(11, LOW);
  Serial.print("Red time left: ");
  Serial.print(red);
  Serial.println("seconds");
  delay(1000);
  }

 for (int green = 12; green>=0; green--) {
  digitalWrite(13, LOW);
  digitalWrite(12, HIGH);
  digitalWrite(11, LOW);
  Serial.print("Green time left: ");
  Serial.print(green);
  Serial.println("seconds");
  delay(1000);
  }
  
  for (int yellow = 3; yellow>=0; yellow--) {
  digitalWrite(13, LOW);
  digitalWrite(12, LOW);
  digitalWrite(11, HIGH);
  Serial.print("Yellow time left: ");
  Serial.print(yellow);
  Serial.println("seconds");
  delay(1000);
  }
  


}