void setup() {
  pinMode(0, OUTPUT);         // Set pin '0' to OUTPUT mode
  int iterations = 0;         // Initialize 'iterations' variable with value 0

  while (iterations < 3) {    // Continue until three iterations are completed
    iterations = iterations + 1; // Increase iteration count by one
    digitalWrite(0, HIGH);
    delay(500);
    digitalWrite(0, LOW);
    delay(500);
  }
}

void loop() {
  // Not used in this exercise
}