int ledPin = D2;
int cnt = 5;

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

void loop() {
    for(int i = 0; i < cnt; i++){
        // First... On
        digitalWrite(ledPin, HIGH);   // Turn ON the LED pins
        delay(500);  
        // Now... Off
        digitalWrite(ledPin, LOW);   // Turn OFF the LED pins
        delay(500);               // Wait for 500mS = .5 second
    }
    delay(2500);
}