const int LED_PIN = 12;
const unsigned long BLINK_RATE[] = {500, 1000, 500};

bool ledState = false;
unsigned long prevTime = 0;

bool blinkLed(unsigned long speed, int number) {
  bool isDone = false;
  static int count = 0;

  if (millis() - prevTime >= speed) {
    ledState = !ledState;
    digitalWrite(LED_PIN, ledState);
    count++;
    if (count >= number * 2)  {
      count = 0;
      isDone = true;
    } else  {
      //isDone = false;
    }
    prevTime = millis();
  }
  return isDone;
}

void setup() {
  Serial.begin(115200);
  pinMode(LED_PIN, OUTPUT);
}

void loop() {
  //static bool isDone = false;

  for (int i = 0; i < 3; i++) {
    Serial.println(i);
    bool isDone = false;
    do {
      isDone = blinkLed(BLINK_RATE[i], 3);
    }
    while (!isDone);
    
    
  }
}