#define LED_1 18
#define LED_2 19
#define LED_3 21

int counter = 0;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  Serial.println("Hello, ESP32!");

  pinMode(LED_1, OUTPUT);
  pinMode(LED_2, OUTPUT);
  pinMode(LED_3, OUTPUT);

}

void loop() {
  
  delay(1000);

  if(counter == 0)
  {
    digitalWrite(LED_1, LOW);
    digitalWrite(LED_2, LOW);
    digitalWrite(LED_3, LOW);
    delay(500);
    counter = counter + 1;
  }
  else if(counter == 1)
  {
    digitalWrite(LED_1, HIGH);
    digitalWrite(LED_2, LOW);
    digitalWrite(LED_3, LOW);
    delay(500);
    counter = counter + 1;
  }
  else if(counter == 2)
  {
    digitalWrite(LED_1, LOW);
    digitalWrite(LED_2, HIGH);
    digitalWrite(LED_3, LOW);
    delay(500);
    counter = counter + 1;
  }
  else if(counter == 3)
  {
    digitalWrite(LED_1, HIGH);
    digitalWrite(LED_2, HIGH);
    digitalWrite(LED_3, LOW);
    delay(500);
    counter = counter + 1;
  }
  else if(counter == 4)
  {
    digitalWrite(LED_1, LOW);
    digitalWrite(LED_2, LOW);
    digitalWrite(LED_3, HIGH);
    delay(500);
    counter = counter + 1;
  }
  else if(counter == 5)
  {
    digitalWrite(LED_1, HIGH);
    digitalWrite(LED_2, LOW);
    digitalWrite(LED_3, HIGH);
    delay(500);
    counter = counter + 1;
  }
  else if(counter == 6)
  {
    digitalWrite(LED_1, LOW);
    digitalWrite(LED_2, HIGH);
    digitalWrite(LED_3, HIGH);
    delay(500);
    counter = counter + 1;
  }
  else if(counter == 7)
  {
    digitalWrite(LED_1, HIGH);
    digitalWrite(LED_2, HIGH);
    digitalWrite(LED_3, HIGH);
    delay(500);
    counter = counter + 1;
  }
  else{
    counter = 0;
  }


}