int redLed = 8;

void setup() {
  // put your setup code here, to run once:
  pinMode(redLed, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  repetBlink(3,redLed,300);
  delay(600);
  
  repetBlink(3,redLed,900);

  repetBlink(3,redLed,300);

  delay(1800);
}


//a function trun on and off the LED, input parameters are: input pin, the period of on and off
void blink(int led, long seconds) 
{
    digitalWrite(led, HIGH);
    delay(seconds);
    digitalWrite(led, LOW);
    delay(seconds);
}

//a function to decide how many time it blinked
void repetBlink(int loops,int led, long seconds)
{
  int8_t i;
  for(i = 0; i < loops ; i ++)
  {
     blink(led, seconds);
  }
}