void setup() {
  pinMode(LED_BUILTIN, OUTPUT); // Set pin 13 as an output pin
}

void loop() {
  digitalWrite(LED_BUILTIN, HIGH); // Turn ON the LED connected to pin 13
  delay(500); // Wait for 1000 milliseconds (1 second)
  
  digitalWrite(LED_BUILTIN, LOW); // Turn OFF the LED connected to pin 13
  delay(500); // Wait for 1000 milliseconds (1 second)
}