int ledPin = D2;

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

void loop() {

  // Exercise 2
  for (int i = 0; i < 5; i++) {
      digitalWrite(ledPin, HIGH);
      delay(500); 
      digitalWrite(ledPin, LOW);
      delay(500);  
  }
  
   delay(3000); 

}