int LED = 12;             // call pin 12 "LED" for the rest of this sketch

void setup() {
  pinMode(LED, OUTPUT);   // make the LED pin an output
}

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