// sketch 01_02_blink_fast_slow
int ledPin = 13;

void setup()
{
  pinMode(ledPin, OUTPUT);
  flash(10, 100);
}

void loop()
{
  flash(1, 500);
}

void flash(int n, int delayPeriod)
{
  for (int i = 0; i < n; i++)
  {
    digitalWrite(ledPin, HIGH);
    delay(delayPeriod);
    digitalWrite(ledPin, LOW);
    delay(delayPeriod);
  }
}