const int red_pin = 2;
const int yellow_pin = 3;
const int green_pin = 4;
//Red wire is for red light.
//Yellow Wire is for yellow light.
//Green Wire is for green light.
//Black Wire is for GND.
void setup()
{
pinMode(red_pin, OUTPUT);
pinMode(yellow_pin, OUTPUT);
pinMode(green_pin, OUTPUT);
}


void loop()
{
  digitalWrite(green_pin , HIGH);
  delay(5000);
  digitalWrite(green_pin, LOW);



  digitalWrite(yellow_pin, HIGH);
  delay(5000);
  digitalWrite(yellow_pin, LOW);


  digitalWrite(red_pin, HIGH);
  delay(5000);
  digitalWrite(red_pin, LOW);
}