int led = D2;

void setup() {
  // We want to tell the Argon that we'll use
  // D2 as an output pin.
  pinMode(led, OUTPUT);
}

void loop() {
    for(int i = 0; i < 5; i++) {
        digitalWrite(led, HIGH);
        delay (500);
        
        digitalWrite(led, LOW);
        delay (500);
    }
    digitalWrite(led, LOW);
    delay(3000);
}