void setup() {              // runs once when you press reset or power the board
  pinMode(12, OUTPUT);      // make digital pin 12 an output
}

void loop() {               // runs over and over again, forever
  digitalWrite(12, HIGH);   // turn the LED on (HIGH is the voltage level)
  delay(1000);              // wait for one second (1000 milliseconds)
  digitalWrite(12, LOW);    // turn the LED off (LOW)
  delay(1000);              // wait for one second
}