#define led_y 12  //Define the yellow led pin to 12

void setup() {    //The code inside the setup function runs only once
  pinMode(led_y, OUTPUT);  //Set pin to output mode
}

void loop() {     //The code inside the loop function will always run in a loop
  digitalWrite(led_y, HIGH);  //Light up the LED
  delay(200);     //Delay statement, in ms
  digitalWrite(led_y, LOW);   //Close the LED
  delay(200);
}