#define LED2_PIN 12
// the setup function runs once when you press reset or power the board
void setup() {
  // initialize digital pin LED_BUILTIN as an output.
  pinMode(LED2_PIN, OUTPUT);
  pinMode(LED_BUILTIN, OUTPUT);
}

// the loop function runs over and over again forever
void loop() {

      digitalWrite(LED2_PIN, HIGH);  // turn the LED on (HIGH is the voltage level)
      digitalWrite(LED_BUILTIN, LOW);
      delay(1000);                      // wait for a second
      digitalWrite(LED2_PIN, LOW);   // turn the LED off by making the voltage LOW
      digitalWrite(LED_BUILTIN, HIGH);
      delay(1000);  
                    // wait for a second
}